Magneto-transport in high g-factor, low-density two-dimensional electron systems confined in In_0.75Ga_0.25As/In_0.75Al_0.25As quantum wells

TL;DR

This study investigates magneto-transport properties of high-mobility 2D electron systems in In_0.75Ga_0.25As/In_0.75Al_0.25As quantum wells, revealing many-body effects, tunable g-factors, and spin phenomena through quantum Hall and tilted-field measurements.

Contribution

It provides new insights into many-body effects and tunable spin properties in high-mobility 2DES confined in InGaAs/InAlAs quantum wells, using combined magneto-transport and resonance techniques.

Findings

Observation of multiple quantum Hall states across various temperatures and densities.

Determination of a large, filling factor dependent effective g-factor.

Evidence of exchange-correlation energy changes at magnetic transitions.

Abstract

We report magneto-transport measurements on high-mobility two-dimensional electron systems (2DESs) confined in In_0.75Ga_0.25As/In_0.75Al_0.25As single quantum wells. Several quantum Hall states are observed in a wide range of temperatures and electron densities, the latter controlled by a gate voltage down to values of 1.10^11 cm^-2. A tilted-field configuration is used to induce Landau level crossings and magnetic transitions between quantum Hall states with different spin polarizations. A large filling factor dependent effective electronic g-factor is determined by the coincidence method and cyclotron resonance measurements. From these measurements the change in exchange-correlation energy at the magnetic transition is deduced. These results demonstrate the impact of many-body effects in tilted-field magneto-transport of high-mobility 2DESs confined in In_0.75Ga_0.25As/In_0.75Al_0.25As quantum wells. The large tunability of electron density and effective g-factor, in addition, make this material system a promising candidate for the observation of a large variety of spin-related phenomena.