AlScN ferroelectric modulates quantum transport in AlGaN/GaN two-dimensional electron gas

Abstract

GaN-based heterojunction two-dimensional electron gas (2DEG) plays a significant role in high-speed microelectronics, high-efficiency photodetectors, and spintronic devices. The integration of wurtzite ferroelectrics with GaN-based heterojunctions offers a promising route for non-volatile control of 2DEG transport properties. However, previous studies have predominantly focused on room-temperature operation and carrier density modulation, while the low-temperature quantum transport properties under ferroelectric gating and their regulation mechanism remain largely unexplored. Here, we demonstrate that an AlScN ferroelectric gate can effectively and reversibly modulate both the carrier density and quantum coherence of the 2DEG in AlGaN/GaN heterostructures at cryogenic temperatures. Through systematic magnetotransport measurements, a significant enhancement of weak localization (WL) under upward ferroelectric polarization was observed, accompanied by a drastic reduction in electron mobility. By analyzing the confinement degree of the 2DEG, we reveal that the ferroelectric polarization not only depletes carriers but also strongly enhances interface scattering by tightening the quantum confinement, thereby amplifying the WL effect and reducing the mobility. Our findings provide insights into the role of ferroelectric polarization in modulating quantum transport and highlight the potential of AlScN for non-volatile, low-power cryogenic memory, and quantum devices.