Currents and current correlations in a topological superconducting nanowire beam splitter

¹ Center of Interdisciplinary Studies & Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University - Lanzhou 730000, China
² Department of Maths and Physics, Hunan Institute of Engineering - Xiangtan 411104, China
³ Beijing Computational Science Research Center - Beijing 100084, China

Received: 28 April 2015
Accepted: 26 August 2015

Abstract

A beam splitter consisting of two normal leads coupled to one end of a topological superconducting nanowire via double quantum dot is investigated. In this geometry, the linear current cross-correlations at zero temperature change signs vs. the overlap between the two Majorana bound states hosted by the nanowire. Under symmetric bias voltages the net current flowing through the nanowire is noiseless. These two features highlight the fermionic nature of such exotic Majorana excitations though they are based on the superconductivity. Moreover, there exists a unique local particle-hole symmetry inherited from the self-Hermitian property of Majorana bound states, which is apparently scarce in other systems. We show that such particular symmetry can be revealed through measuring the currents under complementary bias voltages.