Superconductivity in a Misfit Phase That Combines the Topological Crystalline Insulator Pb_{1}_{x}Sn_{x}Se with the CDWBearing Transition Metal Dichalcogenide TiSe_{2}
Abstract
We report the characterization of the misfit compound (Pb_{1}_{x}Sn_{x}Se_{2})_{1.16}(TiSe_{2})_{2} for 0 ≤ x ≤ 0.6, in which a [100] rocksaltstructure bilayer of Pb_{1}_{x}Sn_{x}Se, which is a topological crystalline insulator in bulk form, alternates with a double layer of the normally nonsuperconducting transition metal dichalcogenide TiSe_{2}. The x dependence of T_{c} displays a weak domelike shape with a maximum T_{c} of 4.5 K at x = 0.2; there is only a subtle change in T_{c} at the composition where the trivial to topological transition occurs in bulk Pb_{1}_{x}Sn_{x}Se. We present the characterization of the superconductor at x = 0.4, for which the bulk Pb_{1}_{x}Sn_{x}Se phase is in the topological crystalline insulator regime. For this material, the Sommerfeld parameter γ = 11.06 mJ mol^{1} K^{2}, the Debye temperature Θ_{D} = 161 K, the normalized specific heat jump value ΔC/γT_{c} = 1.38 and the electronphonon constant value λ_{ep} = 0.72, suggesting that (Pb_{0.6}Sn_{0.4}Se)_{1.16}(TiSe_{2})_{2} is a BCStype weak coupling superconductor. This material may be of interest for probing the interaction of superconductivity with the surface states of a topological crystalline insulator.
 Publication:

Journal of the Physical Society of Japan
 Pub Date:
 June 2016
 DOI:
 10.7566/JPSJ.85.064705
 arXiv:
 arXiv:1602.00018
 Bibcode:
 2016JPSJ...85f4705L
 Keywords:

 Condensed Matter  Superconductivity
 EPrint:
 16 pages, 6 figures