Electric-field-induced two-dimensional hole gas in undoped GaSb quantum wells

We have measured hole transport in electrically induced two-dimensional hole gases in undoped GaSb/AlSb quantum wells. In order to access the electrically induced two-dimensional hole gas in GaSb quantum wells, recessed ohmic contacts were formed and the low-temperature magnetoresistance was measured for a gate-defined Hall bar geometry. The mobility of the sample increases with increasing hole density and reaches 20 000 cm²/V s at a hole density of 5.3 × 10¹¹ cm^-2 for an 8-nm-thick GaSb quantum well. The longitudinal and Hall resistivities show Shubnikov-de Haas oscillations and integer quantum Hall plateaus, respectively. These results establish a platform for realizing spin-based electronics using the strong spin-orbit interaction of this material and are also useful for understanding the transport properties of the two-dimensional topological insulator realized in InAs/GaSb double quantum well structures.