Detection of Majorana Kramers Pairs Using a Quantum Point Contact

Jian Li, Wei Pan, B. Andrei Bernevig, Roman M. Lutchyn

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42 Scopus citations


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.

Original languageEnglish (US)
Article number046804
JournalPhysical review letters
Issue number4
StatePublished - Jul 20 2016

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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