报告题目：Magnetism of LaAlO₃/SrTiO₃Heterostructure Interface

报 告 人：Lu Li, University of Michigan

报告时间：12月13日（周四）下午2:00

报告地点：物理系B406会议室

报告摘要：The LaAlO₃/SrTiO₃heterostructure is a potential candidate for a high mobility two-dimensional electron system with novel electronic and magnetic properties. Although LaAlO₃and SrTiO₃are both large-gap band insulators, the interface is conductive, and even superconducting below 200 mK. Negative electronic compressibility is observed as the carrier density is tuned through electric field effect [1]. Magneticordering has been proposed to arise from the d-electrons transferred by polarization discontinuity. However the magnetization of this system has not previously been studied, because of the small volume of the interface. Using torque magnetometry, we detect the magnetic moment of the interface system directly [2]. Our results indicate the existence of a magnetic ordering at the two-dimensional conductive interface. More importantly, the same magnetic behavior persists even when the sample is superconducting, which suggests an unconventional two-dimensional superconducting phase.

References:

[1] Lu Li, C. Richter, S. Paetel, T. Kopp, J. Mannhart, and R. C. Ashoori, Science 332, 825 (2011)

[2] Lu Li, C. Richter, J. Mannhart, and R. C. Ashoori Nature Physics 7, 762 (2011)