Spin-singlet superconductivity in doped topological crystalline insulator Sn_{0.96}In_{0.04}Te

Abstract

The In-doped topological crystalline insulator Sn_{1-x}In_xTe is a candidate for a topological superconductor, where pseudo-spin-triplet state has been proposed. To clarify the spin symmetry of Sn_{1-x}In_xTe, we perform ^{125}Te-nuclear magnetic resonance (NMR) measurements in polycrystalline samples with 0< x <0.15. The penetration depth calculated from the NMR line width is T-independent below half the superconducting transition temperature (T_c) in polycrystalline Sn_{0.96}In_{0.04}Te, which indicates a fully-opened superconducting gap. In this sample, the spin susceptibility measured by the spin Knight shift (K_s) at an external magnetic field of H_0 = 0.0872 T decreases below T_c, and K_s(T=0)/K_s(T=T_c) reaches to 0.36 \pm 0.10, which is far below the limiting value 2/3 expected for a spin-triplet state for a cubic crystal structure. Our result indicates that polycrystalline Sn_{0.96}In_{0.04}Te is a spin-singlet superconductor.

arXiv comment10 pages, 5 figures

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Cited by in corpus (8)

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• Tailoring band-structure and band-filling in a simple cubic (IV, III) - VI superconductor
• Superconductivity, pairing symmetry, and disorder in the doped topological insulator Sn${}_{1-x}$In${}_x$Te for x $\ge$ 0.10
• Molecular beam epitaxy of superconducting Sn${}_{1-x}$In${}_x$Te thin films
• Superconductivity in Sn${}_{1-x}$In${}_x$Te thin films grown by molecular beam epitaxy
• Unconventional superconductivity from electronic dipole fluctuations
• Non-Trivial Topological Phase in the Sn_{1-x}In_xTe Superconductor