Dirac fermions and superconductivity in the homologous structures (AgxPb1-xSe)(5)(Bi2Se3)(3m) (m=1,2)

作者：Fang L^*; Stoumpos C C; Jia Y; Glatz A; Chung D Y; Claus H; Welp U; Kwok W K; Kanatzidis M G

来源：Physical Review B, 2014, 90(2): 020504.

DOI：10.1103/PhysRevB.90.020504

A newly discovered topological insulator (TI) (AgxPb1-xSe)(5)(Bi2Se3)(3m) (m = 2) has a band gap of 0.5 eV, the largest value reported in topological insulators. We present a magnetotransport study of the Dirac electrons of this compound in the quantum diffusion regime. Two-dimensional weak antilocalization due to the destructive interference of the Dirac electrons was observed. The phase coherence length of the Dirac electrons is independent of doping and disorder levels. This provides an indication of the backscattering immunity under the protection of time reversal invariance of the TI. We further report that the homologous compound (AgxPb1-xSe)(5)(Bi2Se3)(3m) (m = 1) is a superconductor with a transition temperature T-C = 1.7 K. The related structures of these two phases allow lateral intergrowth of crystals to occur naturally, offering a potential platform to observe the Majorana fermion state at the boundary of two intergrown crystals.

• 出版日期2014-7-9
• 单位西北大学