« All Events
Professor Adam Wei TsenUniversity of WaterlooHost: Dan Rhodes (MS&E)
Tunneling Probe of 2D Magnetism
AbstractThe recent discoveries of ferromagnetism in single atomic layers have opened a new avenue for two-dimensional materials research. Not only do they raise fundamental questions regarding the requirements for long-range magnetic order in low dimensions, but they also provide a new platform for the development of spintronic devices. In this talk, I will present a series of studies on the chromium trihalide family of layered ferromagnetic insulators, CrX3 (X = I, Br, Cl), as well as the proximate Kitaev quantum spin liquid candidate, alpha-RuCl3, all in the atomically thin limit. By incorporating these materials as tunnel barriers between graphene or metal electrodes, we are not only able to achieve extremely large tunnel magnetoresistance, but further perform inelastic tunneling spectroscopy to directly observe their spin wave excitations, or magnons, from which we are able to obtain microscopic Hamiltonians for the different spin systems. Our results show that strong anisotropy is not necessary to stabilize ferromagnetism in the monolayer limit and demonstrate the importance of sample dimensionality in tuning layered magnets.
BiographyTsen received his PhD in 2013 in Applied Physics at Cornell University under the guidance of Jiwoong Park. He did postdoctoral work at Columbia University with Abhay Pasupathy and Philip Kim. In 2016, he started his group at the University of Waterloo, which is focused on the study of quantum materials in low dimensions using magnetotransport and optoelectronic techniques.