Density-controlled quantum Hall ferromagnetic transition in a two-dimensional hole system

Abstract

Quantum Hall ferromagnetic transitions are typically achieved by increasing the Zeeman energy through in-situ sample rotation, while transitions in systems with pseudo-spin indices can be induced by gate control. We report here a gate-controlled quantum Hall ferromagnetic transition between two real spin states in a conventional two-dimensional system without any in-plane magnetic field. We show that the ratio of the Zeeman splitting to the cyclotron gap in a Ge two-dimensional hole system increases with decreasing density owing to inter-carrier interactions. Below a critical density of $\sim 2.4\times 10^{10}$ cm${}^{-2}$, this ratio grows greater than $1$, resulting in a ferromagnetic ground state at filling factor $\nu =2$. At the critical density, a resistance peak due to the formation of microscopic domains of opposite spin orientations is observed. Such gate-controlled spin-polarizations in the quantum Hall regime opens the door to realizing Majorana modes using two-dimensional systems in conventional, low-spin-orbit-coupling semiconductors.

References in corpus (7)

• Exotic non-Abelian anyons from conventional fractional quantum Hall states
• Spin susceptibility and effective mass of two-dimensional electrons in MgxZn1-xO/ZnO heterostructures
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• Zeeman splitting of interacting two-dimensional electrons with two effective masses

Cited by in corpus (1)

• Effective g factor of low-density two-dimensional holes in a Ge quantum well