title: Detection of Majorana Kramers Pairs Using a Quantum Point Contact.
abstract: We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. Such a switching of the current represents a qualitative signature where multiterminal differential conductances oscillate with alternating signs when the external magnetic field is tuned. We show that this qualitative signature is also present in current cross-correlations. Thus, the change of the backscattering current nature affects both conductance and shot noise, the measurement of which offers a significant advantage over quantitative signatures such as conductance quantization in realistic measurements.
authors: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors: Jian
authors: J
authors: Li
authors: Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors: Wei
authors: W
authors: Pan
authors: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors: B Andrei
authors: BA
authors: Bernevig
authors: Station Q, Microsoft Research, Santa Barbara, California 93106-6105, USA.
authors: Roman M
authors: RM
authors: Lutchyn