In-plane gate induced transition asymmetry of spin-resolved Landau levels in InAs-based quantum wells

TL;DR

This study investigates how in-plane gate-induced electric fields affect spin-resolved Landau levels in InAs quantum wells, revealing transition asymmetries and spin-dependent backscattering in the quantum Hall regime.

Contribution

It demonstrates the control of spin-split Landau levels via in-plane electric fields and reveals transition asymmetries in InAs-based quantum wells.

Findings

In-plane electric fields shift quantum Hall plateau transitions by ~0.1 T.

High effective g-factor of 16 enables resolving spin-split subbands at 2.5 T.

Spin-dependent backscattering indicates an effective magnetic field of ~0.13 T.

Abstract

The cross-over from quasi-two- to quasi-one-dimensional electron transport subject to transverse electric fields and perpendicular magnetic fields are studied in the diffusive to quasiballistic and zero-field to quantum Hall regime. In-plane gates and Hall-bars have been fabricated from an InGaAs/InAlAs/InAs quantum well hosting a 2DEG with carrier density of about 6.8$\times$10$^{11}$ cm$^{-2}$, mobility of 1.8$\times$10$^5$ cm$^2$/Vs and an effective mass of 0.042$m_e$ after illumination. Magnetotransport measurements at temperatures down to 50 mK and fields up to 12 T yield a high effective Land\'e-factor of |g$^*$| = 16, enabling the resolution of spin-split subbands at magnetic fields of 2.5 T. In the quantum Hall regime, electrostatic control of an effective constriction width enables steering of the reflection and transmission of edge channels, allowing a separation of fully spin-polarized edge channels at filling factors ${\nu}$ = 1 und ${\nu}$ = 2. A change in the orientation of a transverse in-plane electric field in the constriction shifts the transition between Zeeman-split quantum Hall plateaus by ${\Delta}$B $\approx$ 0.1 T and is consistent with an effective magnetic field of B$_{eff}$ $\approx$ 0.13 T by spin-dependent backscattering, indicating a change in the spin-split density of states.