题目：Storing data without moving charge

报告人：Gabriel Aeppli

邀请人：史明

时间：2025年11月17日 (周一）下午14:00

地点：紫金港西区海纳苑8幢215报告厅

摘要：

Modern electronics relies on the gating and readout of charge. Devices are based on silicon where states are represented by the presence or absence of charge, which must be moved entirely and is therefore costly in energy. Strongly correlated electron systems where the charge is maintained in the memory layer of a device but there is a near degeneracy between insulating and metallic states offer a method of storing information without needing a transfer of charge. A good candidate for exhibiting such bistability is the van der Waals material TaS₂, where a “hidden” charge density wave state can be  accessed with optical or electrical pulses and read out via the electrical resistance. While this bistability was discovered a long time ago, questions (1) about its exact microscopic origin, (2) whether optical and electrical pulses are equivalent, and (3) the growth and nucleation of the hidden state in a working device have remained open. Here we describe experimental (in operando X-ray diffraction microscopy) and theoretical (dynamical mean field theory) resolutions of these questions. 

个人简介：

Gabriel Aeppli is professor of physics at ETH Zürich and EPF Lausanne, and head of the Photon Science Division of the Paul Scherrer Institut. All of his degrees are from MIT and include a BSc in Mathematics and Electrical Engineering, and MSc and PhD in Electrical Engineering. A large fraction of his career was in industry, where, starting as a work-study student at IBM and after his PhD moving to Bell Laboratories and then NEC, he worked on problems ranging from liquid crystals to magnetic data storage. He was subsequently co-founder and director of the London Centre for Nanotechnology and Quain Professor at University College London. Gabriel Aeppli also cofounded the Bio-Nano Consulting Company, of which he remains a non-executive director. He is a frequent advisor to numerous private and public entities worldwide (including China, Australia, Europe and the US) engaged in the funding, evaluation and management of science and technology. Honours include an European Research Council Award, the Mott Prize of the Institute of Physics (London), the Oliver Buckley prize of the American Physical Society, the Néel Medal/International Magnetism Prize of the International Union of Pure and Applied Physics, and election to the (US) National Academy of Sciences, the American Academy of Arts and Sciences, and the Royal Society (London).