Spin-polarized two-dimensional electron gas in undoped Mg xZn 1-xO/ZnO heterostructures

Abstract

Quantum transport properties of two-dimensional electron gas (2DEG) in undoped Mg xZn 1-xO/ZnO heterostructures grown by metal organic vapor phase epitaxy have been investigated. A large zero-field spin-splitting energy more than 15 meV in the 2DEG is determined at 1.6 K. Meanwhile, ferromagnetism is observed in the heterostructures. The findings reveal that the 2DEG is spin polarized at zero magnetic fields. It is believed that the exchange interaction between the itinerant electrons in the two-dimensional channel and the magnetic polarons in the Mg xZn 1-xO barrier around the interface results in the spin polarization of the 2DEG. © 2012 American Institute of Physics.