Gate defined wires in HgTe quantum wells: from Majorana fermions to spintronics

TL;DR

This paper proposes a new platform using gate-defined HgTe quantum wells for Majorana zero-modes and spintronics, highlighting their exceptional tunability of spin-orbit coupling and g-factors for quantum applications.

Contribution

It introduces a novel HgTe quantum well system with highly tunable subband parameters, enabling low-field Majorana modes and improved fabrication of quantum networks.

Findings

Rashba spin-orbit energies tunable up to ~30K

Effective g-factors exceeding 600 achievable

Supports Majorana modes at low magnetic fields

Abstract

We introduce a promising new platform for Majorana zero-modes and various spintronics applications based on gate-defined wires in HgTe quantum wells. Due to the Dirac-like band structure for HgTe the physics of such systems differs markedly from that of conventional quantum wires. Most strikingly, we show that the subband parameters for gate-defined HgTe wires exhibit exquisite tunability: modest gate voltage variation allows one to modulate the Rashba spin-orbit energies from zero up to ~30K, and the effective g-factors from zero up to giant values exceeding 600. The large achievable spin-orbit coupling and g-factors together allow one to access Majorana modes in this setting at exceptionally low magnetic fields while maintaining robustness against disorder. As an additional benefit, gate-defined wires (in HgTe or other settings) should greatly facilitate the fabrication of networks for refined transport experiments used to detect Majoranas, as well as the realization of non-Abelian statistics and quantum information devices.