Majorana bound states in two-channel time-reversal-symmetric nanowire systems

TY - JOUR

T1 - Majorana bound states in two-channel time-reversal-symmetric nanowire systems

AU - Gaidamauskas, Erikas

AU - Paaske, Jens

AU - Flensberg, Karsten

PY - 2013/12/1

Y1 - 2013/12/1

N2 - We consider time-reversal-symmetric two-channel semiconducting quantum wires proximity coupled to a conventional s-wave superconductor. We analyze the requirements for a nontrivial topological phase and find that the necessary conditions are (1) the determinant of the pairing matrix in channel space must be negative, (2) inversion symmetry must be broken, and (3) the two channels must have different spin-orbit couplings. The first condition can be implemented in semiconducting nanowire systems where interactions suppress intra-channel pairing, while the inversion symmetry can be broken by tuning the chemical potentials of the channels. For the case of collinear spin-orbit directions, we find a general expression for the topological invariant by block diagonalization into two blocks with chiral symmetry only. By projection to the low-energy sector, we solve for the zero modes explicitly and study the details of the gap closing, which in the general case happens at finite momenta.

AB - We consider time-reversal-symmetric two-channel semiconducting quantum wires proximity coupled to a conventional s-wave superconductor. We analyze the requirements for a nontrivial topological phase and find that the necessary conditions are (1) the determinant of the pairing matrix in channel space must be negative, (2) inversion symmetry must be broken, and (3) the two channels must have different spin-orbit couplings. The first condition can be implemented in semiconducting nanowire systems where interactions suppress intra-channel pairing, while the inversion symmetry can be broken by tuning the chemical potentials of the channels. For the case of collinear spin-orbit directions, we find a general expression for the topological invariant by block diagonalization into two blocks with chiral symmetry only. By projection to the low-energy sector, we solve for the zero modes explicitly and study the details of the gap closing, which in the general case happens at finite momenta.

KW - cond-mat.mes-hall

KW - cond-mat.supr-con

U2 - 10.1103/PhysRevLett.112.126402

DO - 10.1103/PhysRevLett.112.126402

M3 - Journal article

SN - 0031-9007

VL - 112

JO - Physical Review Letters

JF - Physical Review Letters

IS - 12

M1 - 126402

ER -