| 报告题目 | Magnetism of LaAlO3/SrTiO3 Heterostructure Interface |
| 报告人 | Prof. Li Lu |
| 报告人单位 | Assistant Professor, Department of Physics, University of Michigan, Ann Arbor, MI |
| 报告时间 | 2013-05-28 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室 |
| 主办单位 | 合肥微尺度物质科学国家实验室 |
| 报告介绍 | Personal statement:
My research interest lies in quantum correlated physics in novel materials, such as oxide interfaces, topological insulators and superconductors, high temperature superconductors, and frustrated magnets. We develop innovative experimental tools to explore crucial signatures of novel phenomena in new materials. As a Ph.D. student at Princeton University, I invented a new technique to measure magnetic torque of small samples, with ultrasensitive resolution and great availability to extreme conditions (temperature from 20 mK to 300 K, magnetic field up to 45 T, samples from small single crystals to single atomic layered interface.) During my postdoctoral research at MIT, I also developed new methods to probe electronic density of states using capacitance spectroscopy. Starting my own group in the University of Michigan, we plan to focus on the quantum correlated physics at oxide interfaces, to study how combining interface engineering with correlation in transition metal oxides lead to novel phenomena and practical applications for future electronics.
Abstract:
The LaAlO3/SrTiO3 heterostructure is a potential candidate for a high mobility two-dimensional electron system with novel electronic and agnetic properties. Although LaAlO3 and SrTiO3 are 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]. Magnetic ordering 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.
[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) |
