Date: 2025-11-18
Time: 15:00
Venue: M234
Speaker: Professor Steven Kivelson
                 Stanford University

报告人简介:

Steven Allan Kivelson is an American theoretical physicist renowned for his significant contributions to condensed matter theory. He received his Ph.D. from Harvard in 1979, conducted postdoctoral research with J. Robert Schrieffer, and has held faculty positions at SUNY Stony Brook, UCLA, and Stanford, where he was named the Prabhu Goel Family Professor of Physics in 2012.

Kivelson was awarded the Guggenheim fellowship in 1995, was elected to the American Academy of Arts and Sciences in 2001, and to the National Academy of Sciences in 2010. He won the APS Buckley Prize of 2025 in Condensed Matter Physics. He is the co-editor in Chief of Nature Partner Journal Quantum Materials, published in partnership with Nanjing University.

报告摘要：

Theoretical and experimental studies of two-dimensional electron systems (2DES) have played a pivotal role in the history of quantum condensed matter physics. It is also an old, and long-studied problem, about which much is known. In this talk, I will describe some new results obtained by some brilliant collaborators of mine concerning the quantum phases of the 2DES at large and intermediate values of r_s, where r_s is the Wigner-Seitz radius of the 2DES in units of the effective Bohr radius.These include two new results for the simple 2DES: 1) A more complete analysis of tunneling processes deep in the Wigner crystal (WC) phase (large r_s), which in particular provides suggestive evidence of a self-doping instability.2) A variational Monte Carlo (VMC) study of the phase diagram in the presence of screening gates, yielding a quantitative estimate of the critical gate-distance necessary for the existence of a WC. We also explore several new aspects of multi-component 2DES (i.e. that arises in a multi-valley semiconductor): 1) An asymptotic large r_s examination of valley ordering in the WC phase. 2) Combined VMC and approximate analytic studies of generalized ferromagnetism in the fluid phases at intermediate r_s, including the observation of a spin unpolarized electron-nematic phase in a two-valley 2DES of the sort that occurs in AlAs heterostructures.

联系人：胡江平 研究员 （8264 9818）

           汪自强 教授