Anisotropic g-Factor and Spin-Orbit Field in a Ge Hut Wire Double Quantum Dot

TL;DR

This paper characterizes the anisotropic g-factor and spin-orbit field in a Ge hut wire double quantum dot, revealing strong spin-orbit interaction and relaxation mechanisms crucial for quantum computing applications.

Contribution

It provides the full g-tensor and spin-orbit field orientation in Ge hut wire double dots, advancing understanding of hole spin dynamics for quantum information processing.

Findings

Full g-tensor extracted from anisotropic leakage current

Spin-orbit field is in-plane with a 59° azimuthal angle

Identified two spin relaxation mechanisms: cotunneling and spin-orbit interaction

Abstract

Holes in nanowires have drawn significant attention in recent years because of the strong spin-orbit interaction, which plays an important role in constructing Majorana zero modes and manipulating spin-orbit qubits. Here, from the strongly anisotropic leakage current in the spin blockade regime for a double dot, we extract the full g-tensor and find that the spin-orbit field is in plane with an azimuthal angle of 59{\deg} to the axis of the nanowire. The direction of the spin-orbit field indicates a strong spin-orbit interaction along the nanowire, which may have originated from the interface inversion asymmetry in Ge hut wires. We also demonstrate two different spin relaxation mechanisms for the holes in the Ge hut wire double dot: spin-flip cotunneling to the leads, and spin-orbit interaction within the double dot. These results help establish feasibility of a Ge-based quantum processor.