Entangled end states with fractionalized spin projection in a time-reversal-invariant topological superconducting wire

ALIGIA, ARMANDO A.; ARRACHEA, LILIANA

Physical Review B

American Physical Society

Año: 2018 vol. 98

2469-9950

We study the ground state and low-energy subgap excitations of a finite wire of a time-reversal-invariant topological superconductor (TRITOPS) with spin-orbit coupling. We solve the problem analytically for a long chain of a specific one-dimensional lattice model in the electron-hole symmetric configuration and numerically for other cases of the same model. We present results for the spin density of excitations in long chains with an odd number of particles. The total spin projection along the axis of the spin-orbit coupling Sz=±1/2 is distributed with fractions ±1/4 localized at both ends and shows even-odd alternation along the sites of the chain. We calculate the localization length of these excitations and find that it can be well approximated by a simple analytical expression. We show that the energy E of the lowest subgap excitations of the finite chain defines tunneling and entanglement between end states. We discuss the effect of a Zeeman coupling ΔZ on one of the ends of the chain only. For ΔZ