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Covalent 2D magnets and heterostructures

Speaker Prof. Hao ZENG
Affiliation Department of Physics, University at Buffalo, the State University of New York, USA
Date May 24, 2024 (Friday)
Time 10:30 a.m.
Venue Room 522, 5/F, Chong Yuet Ming Physics Building, The University of Hong Kong


The recent realization of atomically thin vdW magnets by exfoliation and characterization of 2D magnets down to the monolayer limit has rekindled interest in 2D magnetism. However, most of the existing research has focused on a limited number of exfoliated vdW systems, many of which possess relatively low magnetic ordering temperatures and are often chemically unstable. In this talk, I will explore a class of lesser explored materials dubbed covalent 2D magnets. These 2D magnets emerge from the self-intercalation of native 3d transition metal atoms in between layers of transition metal dichalcogenides, forming ultrathin, covalently bonded layered magnets denoted by the chemical formula M1+dX2. The degree of self-intercalation provides a unique mechanism to control exchange coupling, magnetic order, and spin texture, presenting a distinct avenue for the manipulation of 2D magnetism. I will first talk about the synthesis of these materials, focusing on Cr2Te3 and Fe3Se4, as well as 2D magnet/2D semiconductor heterostructures. Subsequently, I will delve into their magnetic properties and unconventional anomalous Hall effect (AHE), which we attribute to the intrinsic band structure associated with the intercalated cations with canted spin moment. We suggest that AHE can be used to probe spin texture and self-intercalation provides an additional tuning knob for the Berry curvature and AHE.



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  6. Gong C. et al., Nat Comm 14, 3839 (2023)



Hao Zeng is the Moti Lal Rustgi Professor of Physics at the Department of Physics, University at Buffalo (UB), the State University of New York. He received his B.S. degree from Nanjing University, China in 1993 and Ph.D. from University of Nebraska-Lincoln in 2001, both in physics. He was a postdoctoral fellow at IBM Thomas J Watson Research Center between 2001 and 2004. He then joined UB as an Assistant Professor. In 2014 he was promoted to full Professor. He is the recipient of an IBM Research Division Award, NSF CAREER Award and SUNY Chancellor’s Award for Excellence in Scholarship and Creative Activities. He is an editor of the Journal of Magnetism and Magnetic materials. He has published 150 papers with a total cited of 23,000 times. Hao Zeng’s research area is in condensed matter and materials physics. His present research interests focus on nanoscale magnetism and spintronics, unconventional chalcogenide semiconductors and bio-applications of magnetic nanoparticles.


Anyone interested is welcome to attend.