82 research outputs found
Indium substitution effect on the topological crystalline insulator family (PbSn)InTe: Topological and superconducting properties
Topological crystalline insulators (TCIs) have been of great interest in the
area of condensed matter physics. We investigated the effect of indium
substitution on the crystal structure and transport properties in the TCI
system (PbSn)InTe. For samples with a tin
concentration , the low-temperature resisitivities show a dramatic
variation as a function of indium concentration: with up to ~2% indium doping
the samples show weak-metallic behavior, similar to their parent compounds;
with ~6% indium doping, samples have true bulk-insulating resistivity and
present evidence for nontrivial topological surface states; with higher indium
doping levels, superconductivity was observed, with a transition temperature,
Tc, positively correlated to the indium concentration and reaching as high as
4.7 K. We address this issue from the view of bulk electronic structure
modified by the indium-induced impurity level that pins the Fermi level. The
current work summarizes the indium substitution effect on (Pb,Sn)Te, and
discusses the topological and superconducting aspects, which can be provide
guidance for future studies on this and related systems.Comment: 16 pages, 8 figure
Nanocalorimetric Evidence for Nematic Superconductivity in the Doped Topological Insulator SrBiSe
Spontaneous rotational-symmetry breaking in the superconducting state of
doped has attracted significant attention as an
indicator for topological superconductivity. In this paper, high-resolution
calorimetry of the single-crystal
provides unequivocal evidence of a two-fold rotational symmetry in the
superconducting gap by a \emph{bulk thermodynamic} probe, a fingerprint of
nematic superconductivity. The extremely small specific heat anomaly resolved
with our high-sensitivity technique is consistent with the material's low
carrier concentration proving bulk superconductivity. The large basal-plane
anisotropy of is attributed to a nematic phase of a two-component
topological gap structure and caused by a
symmetry-breaking energy term .
A quantitative analysis of our data excludes more conventional sources of this
two-fold anisotropy and provides the first estimate for the symmetry-breaking
strength , a value that points to an onset transition of
the second order parameter component below 2K
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