VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013


 Nanophysics: from fundamentals to applications

(the return)


Thursday 8
Topological Insulators

› 16:30 - 16:50 (20min)
Transport theory for superconducting topological insulators
Ai Yamakage  1@  
1 : Department of Applied Physics, Nagoya University
Furo-cho, Chikusa-ku, Nagoya 464-8603 -  Japan

We study Andreev bound states (ABSs) and tunneling conductance in a superconducting topological insulator (STI). STI is a superconductor composed of a carrier-doped topological insulator, and can become a topological superconductor, which supports Majorana fermions as ABSs. In STIs, by tuning the chemical potential and the effective mass of the energy band, a structural transition of ABSs in the momentum space occurs. For the larger chemical potential, the line shape of energy bands of the ABSs is conventional cone-shape (zero energy at zero momentum). On the other hand, for the smaller chemical potential, that is twisted shape (zero energies at zero and nonzero momenta). At the transition point, the surface density of states diverges. Therefore in the vicinity of the transition, the tunneling conductance between normal metal / STI junction shows a robust zero bias peak. On the other hand, well-known three-dimensional full-gapped topological superconductor does not show a zero-bias conductance peak. Our result on the zero-bias conductance peak is consistent with the experimental result of STI Cu-doped Bi2Se3.

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