Hysteretic magnetoresistance and thermal bistability in a magnetic two-dimensional hole system

TL;DR

This study investigates hysteretic magnetoresistance and thermal bistability in Mn-doped InAs quantum wells, revealing magnetic field-driven insulator-metal transitions, magnetic anisotropy effects, and potential for information storage applications.

Contribution

It demonstrates magnetic field and bias voltage-dependent bistability and hysteresis in magnetotransport properties of Mn-doped InAs quantum wells, highlighting the role of exchange coupling and thermal effects.

Findings

Magnetic field induces insulator-to-metal transition with hysteresis.

Exchange coupling causes magnetic anisotropy and bistability.

High bias voltage leads to abrupt resistance jumps due to electron overheating.

Abstract

Colossal negative magnetoresistance and the associated field-induced insulator-to-metal transition, the most characteristic features of magnetic semiconductors, are observed in n-type rare earth oxides and chalcogenides, p-type manganites, n-type and p-type diluted magnetic semiconductors (DMS) as well as in quantum wells of n-type DMS. Here, we report on magnetostransport studies of Mn modulation-doped InAs quantum wells, which reveal a magnetic field driven and bias voltage dependent insulator-to-metal transition with abrupt and hysteretic changes of resistance over several orders of magnitude. These phenomena coexist with the quantised Hall effect in high magnetic fields. We show that the exchange coupling between a hole and the parent Mn acceptor produces a magnetic anisotropy barrier that shifts the spin relaxation time of the bound hole to a 100 s range in compressively strained quantum wells. This bistability of the individual Mn acceptors explains the hysteretic behaviour while opening prospects for information storing and processing. At high bias voltage another bistability, caused by the overheating of electrons10, gives rise to abrupt resistance jumps.