Superconductivity in a Misfit Layered (SnS)1.15(TaS2) Compound

Subscriber access provided by Thompson Rivers University | Library

Article

Superconductivity in a misfit layered (SnS)1.15(TaS2) compound Raman Sankar, G. Peramaiyan, I Panneer Muthuselvam, Cheng-Yen Wen, Xiaofeng Xu, and F. C. Chou Chem. Mater., Just Accepted Manuscript • DOI: 10.1021/acs.chemmater.7b04998 • Publication Date (Web): 22 Jan 2018 Downloaded from http://pubs.acs.org on January 29, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Chemistry of Materials is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Chemistry of Materials

Superconductivity in a misfit layered (SnS)1.15(TaS2) compound Raman Sankar1,2*, G. Peramaiyan1, I. Panneer Muthuselvam1,2,3, Cheng-Yen Wen4, Xiaofeng Xu5,6, and F. C. Chou2,7,8* 1

Institute of Physics, Academia Sinica, Taipei 10617, Taiwan

2

Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan

3

Department of Materials Science, Central University of Tamil Nadu, Neelakudi, Thiruvarur

610005, Tamil Nadu, India. 4

Department of Materials Science and Engineering, National Taiwan University, Taipei 10617,

Taiwan. 5

Advanced Functional Materials Lab and Department of Physics, Changshu Institute of

Technology, Changshu 215500, China 6

Department of Physics, Hangzhou Normal University, Hangzhou 310036, China

7

National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

8

Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology,

Taipei 10622, Taiwan. R.S and G.P contributed equally to this work.

Abstract We report the single crystal growth and superconducting properties of a misfit layered (SnS)1.15(TaS2) compound. The transport, magnetic and thermodynamic properties revealed the superconducting transition with an onset temperature of Tc ~3.01 K. High resolution transmission electron microscopy (HRTEM) image clearly shows the misfit stacking of SnS and TaS2 layers. Based on the Werthamer-Helfand-Hohenberg (WHH) formula and GinzburgLandau theory, the upper critical fields are Hc2(0) = 0.64±0.06 Tesla and 0.22±0.02 Tesla with coherence lengths of ξ = 22.67 nm and 38.68 nm for field applied perpendicular (H ⊥ ) and parallel (H//) to the plane, respectively. Based on the specific heat measurement data analysis of 1 ACS Paragon Plus Environment

Chemistry of Materials 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

derived parameters including Sommerfeld coefficient γ = 5.831 ± 0.012 mJ mol-1 K-2, Debye temperature ΘD = 151 K, specific heat jump ∆Ce/γTc = 0.812, and the electron-phonon coupling constant λel-ph ~0.724, all indicate the weak-coupling nature for (SnS)1.15(TaS2) as a misfit layered superconductor. Resistivity measurements show that Tc increases from temperature 3.01 K to 3.85 K at 1.95 GPa, and linear dependence of Tc as a function of pressure (P) is observed up to 1.583 GPa. *Corresponding authors: Raman Sankar1,2 and F. C. Chou2 Institute of Physics, Academia Sinica, Taipei 10617, Taiwan, 2Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan, Phone: +886 - 02 - 3366 3826. Fax: +886 - 02 - 3366 3843. E-mail: [email protected], [email protected] Introduction The misfit layered compounds attract special attention due to their incommensurate layered structural features that are linked to their unique physical properties1. The transition metal dichalcogenides having incommensurate intercalated layers sandwiched in between have been reported showing superconductivity. The general formula of this class of material is represented as (MX)1+δ(TX2)m with m = 1, 2, 3, where MX represents the monochalcogenides layer of M=Sn, Pb, Bi, Sb, and rare earth elements, and TX2 represents the transition metal dichalcogenides (TMDC) layer including T=transition metal and X = S, Se and Te. It is noted that m denotes the number of TMDC layer stacked before each MX layer is intercalated. In particular, the value of δ (0.08 ≤ δ ≤ 0.28) represents the mismatch index2–12. The non-integer value of δ indicates the degree of layer mismatch, and is related to the tolerance factors, which can be estimated from the corresponding ionic radii13.

2 ACS Paragon Plus Environment

Page 2 of 19

Page 3 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


The 2D structural flexibility under temperature leads to three different phases, including trigonal 1T-TaS214, hexagonal 2H-TaS215, and rhombohedral 3R-TaS216. Among the numerous forms of transition metal dichalcogenides, TaS2 has attracted more attention due the observed charge density wave (CDW) accompanied with chiral charge order and superconducting transition in 2H-TaS217,18. Due to its structural flexibility, it enables organic and inorganic chemical intercalation to reduce the CDW and raise the superconducting transition temperatures. The hexagonal 2H-TaS2 phase shows superconductivity at 0.8 K with CDW onset near ~78 K17, and the Tc raises from 0.8 K to 5.5 K via various organic and inorganic intercalations19. The trigonal 1T-TaS2 shows only a CDW phase transition at 136 K, and superconductivity occurs under the influence of high pressure20. Recently, photoemission microspectrocopy provided experimental evidence for the stabilization of misfit compounds through metal cross substitution (partial transition metal substitution from the TX2 (T = Ti, Nb) layer into the MX (M= Pb, Sn) layer and vice versa), and ab initio electronic-structure calculations predicted that the nonstoichiometric (substitution of Pb by Ta in (PbS)1.14(TaS2)) plays a significant role in stabilization of the misfit layer compounds21,22. Superconducting properties of (SnS)1.15TaS2 misfit layered compound with Tc ~2.9 K and 2.85 K have been reported based on studies using powder samples before6,23,24. Here, we report the detailed procedure for the growth of large size single crystals of (SnS)1.15TaS2. The misfit character has been confirmed with clear pictures obtained with the high resolution transmission electron microscopy (HRTEM). Thorough characterization on (SnS)1.15TaS2 single crystal sample showing superconductivity onset of Tc ~ 3.01 K is provided by electric transport, magnetic susceptibility, and specific heat measurements. We found that the superconducting



transition temperature (Tc) increases linearly up to 3.77 K under pressure of about 1.583 GPa and then start to saturate when the applied pressure reaches 1.95 GPa.

Experimental We have grown (SnS)1.15(TaS2) single crystals by the chemical vapor transport method. The high quality fine powders of Sn (99.99%), Ta (99.99%), and S (99.99%) in the misfit stoichiometric ratios were used to synthesize the title compound. The mixtures were thoroughly ground and sealed in an evacuated quartz tube and heated at 900 °C for several hours. The prereacted product was loaded into vacuum sealed quartz tubes together with iodine as the transporting agent in appropriate quantity of ~1 mg/cm3. A quartz ampoule containing source mixtures was placed in a two zone furnace, where the temperatures for the source powders and growth regions were set at 800 and 950 °C separated by about 40 cm, respectively. After a growth period of 200 hours, good quality single crystals of (SnS)1.15(TaS2) were seen at the end of the ampoules kept at 800 °C. Figures 1(b) shows the as-grown (SnS)1.15(TaS2) crystal. Powder X-ray diffraction (PWXRD) study was carried out on the as-grown crystal plates of the layered compounds (SnS)1.15(TaS2) and 2H-TaS2, as shown in Fig.1(c). The XRD pattern of (SnS)1.15(TaS2) is compared with 2H-TaS2, which confirmed the misfit phase. The PWXRD pattern recorded (00L) planes of preferred orientation for (SnS)1.15(TaS2) indicates that c = 23.7697 Å, which is in accordance with the orthorhombic phase of TaS2 subsystem having a = 5.7406 Å, b = 3.3082 Å, c = 23.7697 Å and SnS having lattice parameters of a = 5.749 Å, b = 5.737 Å, c = 11.8755 Å, respectively25. Since the unit cell parameters for the two subsystems are mutually incommensurate, i.e., the layer misfit must induce rippling plane on one of the 4 ACS Paragon Plus Environment

Page 4 of 19

Page 5 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


subsystem relative to the other. Figure 1 (a) depicts the crystal structure of misfit layered compound (SnS)1.15(TaS2), which consists regular stacking of SnS layers of distorted NaCl-type structure and the 2H-TaS2 layers. It is clearly seen that the Ta sitting in the trigonal prismatic center of six S atoms in TiS6 coordination is similar to that of a typical 2H-TaS226. Figure 2(a)&(b) show the HRTEM image of misfit (SnS)1.15(TaS2), which confirms the regular stacking of SnS and TaS2 layers, which is similar to those reported misfit compounds of (PbS)1.13TaS2 and (SbS)1.16TaS227. Resistivity measurements were performed on the ab-plane of (SnS)1.15(TaS2) crystal by employing the four probe method. The resistivity change as a function of temperature is shown in Fig. 3(a) for both in-plane and cross-plane directions, respectively. For the cross-plane direction, the variation of resistivity above ~50 K is linear to show a metallic behavior with residual resistivity ratio (RRR) about 11, which is comparable to the single crystalline misfit layered compounds reported in the literature, including (BiSe)l.l0(NbSe2) (RRR = 4), (BiS)1.11(NbS2) (RRR = 7), and polycrystalline (SnSe)1.18(TiSe2)2 (RRR = 10)28,29. The expanded view of resistivity vs. temperature plot (inset of Fig. 3(a)) shows the onset of superconducting transition temperature Tc ~3.01 K under ambient pressure. The onset of Tc ~3.01 K for (SnS)1.15(TaS2) is higher than that of the pristine 2H-TaS2 (Tc = 1.90 K)30, and the misfit compounds of (SnS)1.1(NbS2) (Tc = 2.75 K)6 and (PbS)1.14(NbS2) (Tc = 2.72 K)23. The Hall resistivity of (SnS)1.15(TaS2) is found positive with linear dependence of magnetic field up to 9 T at 4 K, as shown in Fig.3(b). The inset shows the temperature dependence of Hall coefficient, which does not show carrier sign change from 300 K down to 4 K. From the field dependence of Hall resistivity, carrier density is calculated to be nh ~ 4.9 × 1021 cm-3 at 4 K. Figure 3(c) shows the influence of pressure on the temperature dependent resistivity of (SnS)1.15(TaS2). For the 5 ACS Paragon Plus Environment


hydrostatic pressure dependent resistivity measurements, samples were loaded into a commercial piston-type pressure cell. The actual pressure of the sample was determined by measuring the superconducting transition temperatures of Pb, the pressure is applied on the (00l) plane. Daphne 7373 oil was applied as the pressure transmission media. The same contacts were used throughout the measurements under different pressures such that the geometric errors in the contact size were identical for different runs. Upon increasing the pressure from ambient value taken to be 0 GPa to 1.95 GPa Tc increases linearly up to 1.583 GPa, and starts to saturate at 1.95 GPa as shown in Fig.3 (d). It is found that an initial slope of 0.5 K/GPa below 1.583 GPa, which then slows down to 0.21 K/GPa, between 1.583 and 1.95 GPa. The similar behavior of Tc under the influence of pressure is observed in a layered 2H-TaS2 compound31, and in the (PbSe)1.16(TiSe2)2 misfit superconductor, the superconducting transition temperature (Tc) is initially suppressed, and then slightly increased with the increase of the applied pressure32. A sharp superconducting transition and linear pressure dependence of Tc below 1.583 GPa in a (SnS)1.15(TaS2) compound need further investigation. The photoemission spectral studies of (SnS)1.15(TaS2) have revealed that the Fermi energy of (SnS)1.15(TaS2) and α-SnS (a p-type semiconductor)33 are at the same level, and the obtained emission spectrum of (SnS)1.15(TaS2) is proposed to be the superposition of the individual spectra of α-SnS and TaS2, and hence no charge transfer from the SnS layer to TaS2 layer34,35. In addition, 2H-TaS2 phase showed negative Hall coefficient below 56 K36, whereas 1T-TaS2 showed positive Hall coefficient below 200 K37. In general, the misfit compounds could be regarded as the combination of the two subsystems. Based on the rigid band model, it is revealed that the electron transfer occurs from MX to TX2 layer leading to negative Hall coefficient, which has been verified with many monolayer type of di- and tri-valent M cations;


Page 6 of 19

Page 7 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


large charge transfer in tri-valent M and less charge transfer in di-valent M was found1,4,38. In the case of (SnS)1.17(NbS2), a p-type metallic conduction was found, which has been proposed due to less charge transfer from Sn2+ 38. The field-dependent Hall resistivity of (SnS)1.15(TaS2) suggests that the introduction of SnS layer would not donate electron (e-) into the TaS2 layer, but the hole doping may be coming from a much less e- transfer as in the case of (SnS)1.17(NbS2) system. Detailed first principles calculation is required to probe the possible reason for the stability of (SnS)1.15(TaS2) compound. The temperature dependent upper critical magnetic fields Hc2 for the cross-plane and in-plane directions are obtained from the resistivity measurement in applied magnetic field between 0-2 Tesla, as shown in Fig.4(a)&(b). The transition widths are broadened and the onsets of Tc are reduced with increasing field, as shown in Fig. 4(c)&(d). The zero temperature limit of the upper critical field Hc2(0) for the Tc is calculated from the WerthamerdH c 2  Helfand-Hohenberg (WHH) formula H c 2 (0) = −0.693Tc   T =Tc  dT 

39

. By fitting the WHH

equation dHc2/dT = -Hc2(0)/0.693Tc, as shown in the inset of Figs.4(c)&(d), Hc2(0) is estimated to be 0.64±0.06 T and 0.22±0.02 T for the cross-plane and in-plane directions, respectively. Using the estimated upper critical field Hc2(0) values, the coherence length ξ is calculated to be 22.67 nm and 38.68 nm for the cross-plane and in-plane directions, respectively following the Ginzburg-Landau theory H c 2 = Φ 0 / 2πξ 2 , where Φ0 is the flux quantum. The coherence length of (SnS)1.15(TaS2) is found to be very close to that of the Sn-based misfit superconductor (SnS)1.17(NbS2)38. Figure 5(a) shows the dc magnetization as a function of temperature M (T) measured at 50 Oe, in zero field (ZFC) and field cooled (FC) cycles for both Hǁc and H ⊥ c orientations. A strong FC diamagnetic signal below ~3 K confirms the Meissner effect with onset of Tc ~ 3.01



K. The significant reduction of FC value below Tc is due to the flux pinning. The AC susceptibility measurement was carried out in various frequencies (1, 10. 100, 500 Hz) using rf field of 1 Oe parallel to the c-axis. The real (χ’) and imaginary (χ”) parts of the AC susceptibilities confirmed the superconducting transition has Tc ~ 3.01 K, as shown in Fig.5(b). Specific heat measurement has also been used to probe the superconducting phase transition. Figure 5(c) shows the specific heat measurement results plotted in Cp/T vs. T2 under the applied fields of 0 and 1 T. The anomaly observed in the specific heat curve confirms the superconducting phase transition of Tc ~3.01 K, but the anomaly is vanished under magnetic field of 1 T, which indicates the Hc2 is at least 1T and in agreement with the Hc2 estimated using resistivity data as shown in Fig.4. Since the measured specific heat contains electronic and lattice contributions, the Sommerfeld coefficient (γ) and the phononic coefficient (β) can be obtained from the linear fit of C p / T = γ + βT 2 , yielding γ = 5.831 ± 0.012 mJ mol-1 K-2 and β = 2.79 ± 0.02 mJ mol-1 K-4. The Sommerfeld coefficient of (SnS)1.15(TaS2) is lower than that of 2H-TaS2 (γ = 8.5 ± 0.10 mJ mol-1 K-2) and its intercalated compounds (7.4 – 9.5 mJ mol-1 K-2)19. The Debye temperature ΘD is then calculated from the relation β = (12π 4 nR) /(5Θ 3D ) to be ~151 K, where n=5 is a number of atoms per unit cell without considering the misfit index and R is the ideal gas constant. The electron-phonon coupling constant λel-ph is calculated to be ~0.724 with the Mcmillan formula40,

λel − ph =

 1.45Tc  ΘD

µ * ln

 1.45Tc 1.04 + ln  ΘD

  − 1.04 

 (1 − 0.62µ * ) 

,

where µ* is the Coulomb pseudo-potential set to be 0.15. The λel-ph value suggests that (SnS)1.15(TaS2) is a weak coupled superconductor41. The specific heat jump from the electronic 8 ACS Paragon Plus Environment

Page 8 of 19

Page 9 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


contribution (Ce) is obtained by subtracting the normal state specific heat i.e phonon contribution Cn from the total. Figure 5(d) shows the plot of C-Cn/T vs T, which yields ∆Ce/γTc~0.812 at the onset of superconducting transition to be lower than the Bardeen–Cooper–Schrieffer (BCS) theoretical value of 1.43, but comparable to those of the misfit superconductors of (SnSe)1.18(TiSe2)2 (0.88)29 and (Pb0.6 Sn0.4 Se)1.16(TiSe2)2 (1.38)42. In summary, large size plate-like single crystals of misfit layered compound (SnS)1.15(TaS2) was synthesized and grown by the chemical vapor transport method. The misfit phase of (SnS)1.15(TaS2) was confirmed by the X-ray diffraction and HRTEM analyses. Electric transport and magnetic property measurements confirmed the superconducting transition with the onset of a critical temperature of ~3.01 K. The upper critical field Hc2(0) is calculated to be 0.64±0.06 T and 0.22±0.02 T for the cross-plane and in-plane directions, respectively. The coherence length ξ estimated following the Ginzburg-Landau theory is 22.67 nm and 38.68 nm for the cross-plane and in-plane orientations, respectively. The specific heat jump of ∆Ce/γTc = 0.812 confirms the bulk superconductivity with a Sommerfeld coefficient γ = 5.831 ± 0.012 mJ mol-1 K-2. The electron-phonon coupling constant λel-ph ~0.724 suggests that the (SnS)1.15(TaS2) misfit layer compound is a weak-coupling BCS superconductor. Acknowledgements R.S and G.P contributed equally to this work. R.S. and F.C.C. acknowledge the support provided by the Academia Sinica research program on Nanoscience and Nanotechnology under project number NM004. F.C.C. acknowledges support from the Ministry of Science and Technology in Taiwan under project number MOST-102-2119-M-002-004. We thank the Nanoscience and Technology thematic research program of Academia Sinica, Taiwan. IPM thanks Department of Science and Technology in India for the support of INSPIRE faculty Award No. DST/INSPIRE/04/2016/002275.



References (1)

Wiegers, G. A. Misfit Layer Compounds: Structures and Physical Properties. Prog. Solid State Chem. 1996, 24, 1–139.

(2)

Nader, A.; Lafond, A.; Briggs, A.; Meerschaut, A.; Roesky, R. Structural Characterization and Superconductivity in the Misfit Layer Compound (LaSe)1.14(NbSe2). Synth. Met. 1998, 97, 147–150.

(3)

Wiegers, G. A.; Zhou, W. Y. The Misfit Layer Compound (SnSe)1.16NbSe2. Mater. Res. Bull. 1991, 26, 879–885.

(4)

Meerschaut, A.; Moëlo, Y.; Cario, L.; Lafond, A.; Deudon, C. Charge Transfer in Misfit Layer Chalcogenides, [(MX)n]1+x(TX2)m: A Key for Understanding Their Stability and Properties. Mol. Cryst. Liq. Cryst. Sci. Technol. Sect. A. Mol. Cryst. Liq. Cryst. 2000, 341, 1–8.

(5)

Harris, F. R.; Standridge, S.; Johnson, D. C. The Synthesis of [(Bi2Te3)x{(TiTe2)y}1.36] Superlattices from Modulated Elemental Reactants. J. Am. Chem. Soc. 2005, 127, 7843– 7848.

(6)

Reefman, D.; Baak, J.; Brom, H. B.; Wiegers, G. A. Superconductivity in Misfit Layer Compounds (MS)nTS2. Solid State Commun. 1990, 75, 47–51.

(7)

Zhou, W. Y.; Meetsma, A.; de Boer, J. L.; Wiegers, G. A. Characterization and Electrical Transport Properties of the Misfit Layer Compounds (BiSe)1.10NbSe2 and (BiSe)1.09TaSe2. Mater. Res. Bull. 1992, 27, 563–572.

(8)

Atkins, R.; Disch, S.; Jones, Z.; Haeusler, I.; Grosse, C.; Fischer, S. F.; Neumann, W.; Zschack, P.; Johnson, D. C. Synthesis, Structure and Electrical Properties of a New Tin Vanadium Selenide. J. Solid State Chem. 2013, 202, 128–133.

(9)

Trump, B. A.; Livi, K. J. T.; McQueen, T. M. The New Misfit Compound (BiSe)1.15(TiSe2)2 and the Role of Dimensionality in the Cux(BiSe)1+δ(TiSe2)n Series. J. Solid State Chem. 2014, 209, 6–12.

(10)

Johnson, D. R. M. and D. B. M. and M. N. C. and A. W. J. and M. F. and D. C. Synthesis and Characterization of Turbostratically Disordered (BiSe)1.15 TiSe2. Semicond. Sci. Technol. 2014, 29, 064004 (1-6).

(11)

Wan, C.; Wang, Y.; Wang, N.; Koumoto, K. Low-Thermal-Conductivity (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) Misfit Layer Compounds for Bulk Thermoelectric Materials. Materials . 2010, 3, 2606-2617.

(12)

Johnson, N. S. G. and J. F. and M. F. and M. B. and D. G. C. and D. C. Synthesis, Structure, and Thermal Conductivity of [(SnSe)1 + y ]n [MoSe2 ]n Compounds. Semicond. Sci. Technol. 2014, 29, 124007 (1-5).

(13)

Brehm, J. A.; Bennett, J. W.; Schoenberg, M. R.; Grinberg, I.; Rappe, A. M. The Structural Diversity of ABS3 Compounds with d0 Electronic Configuration for the B10 ACS Paragon Plus Environment

Page 10 of 19

Page 11 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Cation. J. Chem. Phys. 2014, 140 , 224703-224710. (14)

Anderson, R. M. and T. B. and B. P. and M. S. and O. On the Phase Transitions in 1 T TaS2. Europhysics Lett. 1989, 8, 195-200.

(15)

Gamble, F. R.; DiSalvo, F. J.; Klemm, R. A.; Geballe, T. H. Superconductivity in Layered Structure Organometallic Crystals. Science. 1970, 168, 568-570.

(16)

Jellinek, F. The System Tantalum-Sulfur. J. Less Common Met. 1962, 4 , 9–15.

(17)

Harper, J. M. E.; Geballe, T. H.; DiSalvo, F. J. Thermal Properties of Layered TransitionMetal Dichalcogenides at Charge-Density-Wave Transitions. Phys. Rev. B 1977, 15 , 2943–2951.

(18)

Guillamón, I.; Suderow, H.; Rodrigo, J. G.; Vieira, S.; Rodière, P.; Cario, L.; NavarroMoratalla, E.; Martí-Gastaldo, C.; Coronado, E. Chiral Charge Order in the Superconductor 2H-TaS2. New J. Phys. 2011, 13, 103020 (1-10).

(19)

Schlicht, A.; Schwenker, M.; Biberacher, W.; Lerf, A. Superconducting Transition Temperature of 2H−TaS2 Intercalation Compounds Determined by the Phonon Spectrum. J. Phys. Chem. B 2001, 105, 4867–4871.

(20)

Sipos, B.; Kusmartseva, A. F.; Akrap, A.; Berger, H.; Forro, L.; Tutis, E. From Mott State to Superconductivity in 1T-TaS2. Nat Mater 2008, 7 , 960–965.

(21)

Kalläne, M.; Rossnagel, K.; Marczynski-Bühlow, M.; Kipp, L.; Starnberg, H. I.; Stoltz, S. E. Stabilization of the Misfit Layer Compound (PbS)1.13(TaS)2 by Metal Cross Substitution. Phys. Rev. Lett. 2008, 100 , 065502 (1-4).

(22)

Kabliman, E.; Blaha, P.; Schwarz, K. Ab Initio. Phys. Rev. B 2010, 82, 125308 (1-8).

(23)

Reefman, D.; Koorevaar, P.; Brom, H. B.; Wiegers, G. A. Superconductivity and Fluctuations in Misfit Layer Compounds (MS)nTS2. Synth. Met. 1991, 43, 3775–3780.

(24)

Van Maaren, M. H. Superconductivity in Tin -Group Va Trichalcogenides. Phys. Lett. A 1972, 40, 353–354.

(25)

Oosawa, Y. G. and M. O. and J. A. and M. G. and Y. The Layered Composite Crystal Structure of the Ternary Sulfide, (SnS)1.15 TaS2 “SnTaS3 .” Jpn. J. Appl. Phys. 1993, 32, 760-762.

(26)

Meetsma, A.; Wiegers, G. A.; Haange, R. J.; de Boer, J. L. Structure of 2 H-TaS2. Acta Crystallogr. Sect. C 1990, 46, 1598–1599.

(27)

Radovsky, G.; Popovitz-Biro, R.; Tenne, R. Nanotubes from the Misfit Layered Compounds MS–TaS2, Where M = Pb, Sn, Sb, or Bi: Synthesis and Study of Their Structure. Chem. Mater. 2014, 26 , 3757–3770.

(28)

Nader, A.; Briggs, A.; Gotoh, Y. Superconductivity in the Misfit Layer Compounds (BiSe)1.10(NbSe2) and (BiS)1.11(NbS2). Solid State Commun. 1997, 101, 149–153. 11 ACS Paragon Plus Environment


(29)

Song, Y. J.; Kim, M. J.; Jung, W. G.; Kim, B.-J.; Rhyee, J.-S. Superconducting Properties of the Misfit-Layer Compound (SnSe)1.18(TiSe2)2. Phys. status solidi 2016, 253, 1517– 1522.

(30)

Schmidt, L. Superconductivity in PbNbS3 and PbTaS3. Phys. Lett. A 1970, 31, 551–552.

(31)

Freitas, D. C.; Rodière, P.; Osorio, M. R.; Navarro-Moratalla, E.; Nemes, N. M.; Tissen, V. G.; Cario, L.; Coronado, E.; Garc’\ia-Hernández, M.; Vieira, S.; Núñez-Regueiro, M.; Suderow, H. Strong Enhancement of Superconductivity at High Pressures within the Charge-Density-Wave States of 2H-TaS2 and 2H-TaSe2. Phys. Rev. B 2016, 93, 184512(16).

(32)

Chen, N. Z. W. and S. F. Y. and R. C. and X. F. L. and F. B. M. and C. S. and X. H. Structure and Physical Properties of the Misfit Compounds (PbSe)1.16 (TiSe2 )m (m = 1, 2). Europhysics Lett. 2015, 112, 67007(1-6).

(33)

Xia, J.; Li, X.-Z.; Huang, X.; Mao, N.; Zhu, D.-D.; Wang, L.; Xu, H.; Meng, X.-M. Physical Vapor Deposition Synthesis of Two-Dimensional Orthorhombic SnS Flakes with Strong Angle/temperature-Dependent Raman Responses. Nanoscale 2016, 8, 2063–2070.

(34)

Ettema, A. R. H. F.; Wiegers, G. A.; Haas, C.; Turner, T. S. A LEED and Photoemission Spectroscopy Study of the Surface of the Incommensurate Misfit Layer Compound (SnS)1.16TaS2. Surf. Sci. 1992, 269, 1161–1166.

(35)

Ettema, A. R. H. F. E. and Haas, C. An X-Ray Photoemission Spectroscopy Study of Interlayer Charge Transfer in Some Misfit Layer Compounds. J. Phys. Condens. Matter 1993, 5, 3817-3826.

(36)

Thompson, A. H.; Gamble, F. R.; Koehler, R. F. Effects of Intercalation on Electron Transport in Tantalum Disulfide. Phys. Rev. B 1972, 5, 2811–2816.

(37)

Inada, R.; Ōnuki, Y.; Tanuma, S. Hall Effect of 1T-TaS2 and 1T-TaSe2. Phys. B+C 1980, 99, 188–192.

(38)

Fang, C. M.; Ettema, A. R. H. F.; Haas, C.; Wiegers, G. A.; van Leuken, H.; de Groot, R. A. Electronic Structure of the Misfit-Layer Compound (SnS)1.17 (NbS)2 Deduced from Band-Structure Calculations and Photoelectron Spectra. Phys. Rev. B 1995, 52, 2336– 2347.

(39)

Werthamer, N. R.; Helfand, E.; Hohenberg, P. C. Temperature and Purity Dependence of the Superconducting Critical Field, Hc2. III. Electron Spin and Spin-Orbit Effects. Phys. Rev. 1966, 147, 295–302.

(40)

McMillan, W. L. Transition Temperature of Strong-Coupled Superconductors. Phys. Rev. 1968, 167, 331–344.

(41)

CHARLES P. POOLE, J. Hand Book of Superconductivity; 1990.

(42)

Luo, H.; Yan, K.; Pletikosic, I.; Xie, W.; Phelan, B. F.; Valla, T.; Cava, R. J. Superconductivity in a Misfit Phase That Combines the Topological Crystalline Insulator 12 ACS Paragon Plus Environment

Page 12 of 19

Page 13 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Pb1−xSnxSe with the CDW-Bearing Transition Metal Dichalcogenide TiSe2. J. Phys. Soc. Japan 2016, 85, 064705(1-5).



Fig.1 (a) The crystal structure of (SnS)1.15(TaS2) viewed along the b-axis with incommensurability shown in the SnS layer. Ta, Sn, and S atoms are shown in red, blue, and green colors, respectively. (b) Photograph of the as-grown (SnS)1.15(TaS2) single crystal grown from the chemical vapor transport method. (c) X-ray diffraction patterns of (SnS)1.15(TaS2) (upper panel) and 2H-TaS2 (lower panel) crystals, showing preferred orientation of (00l) planes.


Page 14 of 19

Page 15 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(a)

(b)

Fig.2 HRTEM images of (SnS)1.15(TaS2) compound, (a) is the plane-view along [001] direction, and (b) shows the cross-sectional view revealing the regular stacking of SnS and TaS2 layers. Red, blue, and green colors denote Ta, Sn, and S atoms, respectively.



18

1.2 0.8 0.4

onset

Tc

= 3.01 K

0.0 2

12

4

6

8

10

T (K)

Cross plane In-plane

6

0.8

4.4

0.6 0.4 0.2 0.0

4.0

0

100

200

300

T (K) 3.6 nh ~ 2.155×1020 cm-3

3.2 2.8

0

25 20 15

50

100

150 200 250 300 T (K)

0 GPa 0.317 GPa 0.633 GPa 1.2 GPa 1.583 GPa 1.95 GPa

1

2

3

4

5

6

7

8

9

H (T)

3.8

10

3.6 3.4 3.2

5 0 2.8

0

4.0

Tc (K)

0

(b)

4.8

µΩ cm) ρxy (µ

24

5.2

1.6

RH (cm3/C)

(a) ρxx µµΩ cmξ

ρxx ρµΩ cmµ

30

Ω) ρ (mΩ

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 19

3.0

3.2

3.4

3.6

3.8

4.0

3.0 0.0

4.2

T (K)

0.5

1.0

1.5

2.0

2.5

P (G Pa)

Figure 3 (a) Electrical resistivity for the ab-plane of (SnS)1.15(TaS2) crystal as a function of temperature for the in-plane and cross-plane directions. The inset shows the expanded view of superconducting transition of zero resistance near 3.01 K. (b) Field dependence of Hall resistivity measured at 4 K. The inset shows the temperature dependence of Hall coefficient (RH). (c) Temperature-dependent resistivity of (SnS)1.15(TaS2) under pressure. (d) It shows the evolution of Tc under pressure.


Page 17 of 19

(b)

0.6

0T 0.02 T 0.04 T 0.06 T 0.08 T 0.1 T 0.15 T 0.2 T 0.4 T 0.6 T 1T

1.0

0.5

ρ 0µΩ µΩ cm

0.0 2.0

2.5

3.0

3.5

0T 0.02 T 0.04 T 0.06 T 0.08 T 0.1 T 0.15 T 0.2 T 0.4 T 0.6 T 1T

0.4

0.2

0.0

4.0

2.0

T (K) (c)

-0.08

(dH c2 /dT)T=Tc(T K-1)

0.16

2.5

Hc2(0) = 0.64 ± 0.06 T

0.10

(d)

2.2

2.4

2.6 2.8 Tc (K)

3.0

Hc2(T)

-0.20

0.04

4.0

Hc2(0) = 0.22 ± 0.02 T

-0.14

0.08

-0.16

0.08

3.5

T (K)

-0.12

0.12

3.0

(dHc2 /dT)T=Tc (T K -1 )

ρ µΩ cm

1.5 (a)

Hc2(T)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


-0.16

0.06

-0.18

0.04

2.0 2.2 2.4 2.6 2.8 3.0 Tc (K)

0.02 0.00 1.8

onset

2.1

2.4

2.7

3.0

0.00

3.3

onset

2.2

Tc (K)

2.4

2.6

2.8

3.0

3.2

Tc (K)

Figure 4 (a)&(b) Temperature dependent resistivity measured in various magnetic for the cross-plane (H//c I⊥ ⊥c) and in-plane (H//c I// //c) // directions. (c)&(d) The corresponding temperature dependence of upper critical fields Hc2 taken from the Tc onset. Insets show the WHH fit yielding a zero temperature limit of the upper critical field Hc2(0).



(b)

(a)

χAC (10-3emu/g Oe)

Μ /Η (emu/g Oe)

0.00 ZFC FC

-0.04

H// //c // H = 50 Oe

-0.08 -0.12

0

χ''

10 Hz 100 Hz 500 Hz

-5

H// //c //

-10

-15

χ'

-0.16 1.8

2.1

2.4

2.7

3.0

3.3

3.6

1.8

3.9

T (K)

50 40

[C-Cn]/T (mJ mol-1 K-2)

H=5T H=0T C/T = γ + β Τ 2

(c)

C/T(mJ/mol K)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 19

30 20

γ = 5.831±0.012 mJ mol-1 K-2 β = 2.79±0.020 mJ mol-1 K-4 2.79

10 4

6

8

10

12

14

16

2.1

2.4

2.7

3.0

3.3

3.6

3.9

T (K)

12 (d) 9

∆Ce/γΤc = 0.81

6 3 0 2.0

T2 (K2)

2.5

3.0

3.5

4.0

T (K)

Figure 5 (a) Zero-field cooled (ZFC) and field cooled (FC) magnetization as a function of temperature at 50 Oe. (b) Temperature dependence of AC susceptibilities measured with rf field of 1 Oe in frequencies of 1-500 Hz. (c) Specific heat curves of C/T vs. T2 measured in magnetic fields of H=0 and 1 T. Sommerfeld and phononic coefficients were obtained from the linear fit of C/T = γ + βT2 for Cp under 1 T. (d) Plot of (C-Cn)/T vs. T determines a ∆Ce/γTc value of 0.812, where Cn is the phonon contribution to specific heat.


Page 19 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


TOC Figure


Superconductivity in a Misfit Layered (SnS)1.15(TaS2) Compound

Recommend Documents