Physics colloquium – “Harnessing Spin in α-Sn”

Minghzhong Wu

Colorado State University, Department of Physics

Abstract: Dirac semimetals are a recently discovered topological phase of quantum matter. α-Sn is unique among the Dirac semimetals because it is a single-element material and is therefore relatively easy to grow. Further, it can be transformed into other topological phases, such as a topological insulator or a Weyl semimetal, under strains or external fields. I will discuss our recent experimental work on α-Sn thin films along four directions: (1) Growth of α-Sn thin films by a CMOS-compatible sputtering technique. (2) Large damping enhancement in a ferromagnetic thin film due to the presence of topological surface states in an adjacent α-Sn thin film. (3) Current-induced magnetization switching via topological surface states in an α-Sn/Ag/CoFeB trilayer. (4) Spin-momentum-locking driven large magnetoresistance in α-Sn thin films that scales linearly with both magnetic and electric fields.  These results indicate that topological Dirac semimetal α-Sn holds exciting promise of application in next-generation electronics and quantum technologies.

Biography: Mingzhong Wu received his Ph.D. in Solid State Electronics from Huazhong University of Science and Technology (China) in 1999, joined Colorado State University (CSU) in 2007, and is currently a Professor of Physics at CSU. His research interests include topological quantum materials, spintronics, magnetization dynamics, and nonlinear spin waves. He has authored over 170 technical papers and co-edited a major book on magnetic insulators. He served as an Editor for IEEE Magnetics Letters (2012- 2016) and is currently a Senior Editor for Journal of Alloys and Compound and an Editor for Physics Letters A. He served as the Education Committee Chair (2012-2015) and Finance Chair (2015-2018) of the IEEE Magnetics Society and is currently the Technical Committee Chair of the Society (since 2019). He was named “Professor Laureate” by the CSU College of Natural Sciences for 2019, 2020, and 2021. He was elected IEEE Fellow and APS Fellow in 2021.

All lectures held in CoorsTek 140 unless otherwise noted