Controlling magnetoresistance by tuning semimetallicity through dimensional confinement and heteroepitaxy

Controlling electronic properties via band structure engineering is at the heart of modern semiconductor devices. Here, we extend this concept to semimetals where, using LuSb as a model system, we show that quantum confinement lifts carrier compensation and differentially affects the mobility of the electron and hole-like carriers resulting in a strong modification in its large, nonsaturating magnetoresistance behavior. Bonding mismatch at the heteroepitaxial interface of a semimetal (LuSb) and a semiconductor (GaSb) leads to the emergence of a twodimensional, interfacial hole gas. This is accompanied by a charge transfer across the interface that provides another avenue to modify the electronic structure and magnetotransport properties in the ultrathin limit. Our work lays out a general strategy of using confined thin-film geometries and heteroepitaxial interfaces to engineer electronic structure in semimetallic systems, which allows control over their magnetoresistance behavior and simultaneously provides insights into its origin.

Automated summary

Controlling electronic properties through quantum confinement can modify carrier compensation and affect carrier mobility, leading to changes in magnetoresistance behavior; at the heteroepitaxial interface of a semimetal and a semiconductor, bonding mismatch results in the emergence of a two-dimensional, interfacial hole gas, accompanied by charge transfer across the interface, offering another way to adjust electronic structure and magnetotransport properties.