2024 CAP Congress / Congrès de l'ACP 2024

Interface tunable magnetism in quasi-two-dimensional chromium telluride

29 May 2024, 16:00

30m

SSC Rm 2020 (cap. 80) (Social Science Centre., Western U.)

Invited Speaker / Conférencier(ère) invité(e) Symposia Day (DCMMP - DPMCM) - Fluctuations, interactions and Disorder in Condensed Matter / Fluctuations, interactions et désordre dans la matière condensée (DCMMP) W4-7 Fluctuations, interactions and Disorder in Condensed Matter | Fluctuations, interactions et désordre dans la matière condensée (DPMCM)

Speaker

Prof. Hang Chi (University of Ottawa)

Description

Novel quasi-2D magnets are attracting much attention recently. The MBE synthesis route is highly desirable for interface control when implementing strain engineering and/or hybridizing with other quantum systems. In situ prepared atomically sharp interfaces further enable fundamentally new phenomena, while providing opportunities in spintronics, leveraging interface-driven versatility [1]. Ferromagnetic Cr${}_2$Te${}_3$ ultrathin films, optimally grown on Al${}_2$O${}_3$(0001) and SrTiO${}_3$(111), manifest an extraordinary sign reversal in the anomalous Hall conductivity as temperature and/or strain are modulated. It turns out that the nontrivial Berry curvature in the electronic-structure momentum space is responsible for this exotic behavior [2]. Moreover, when proximitized with (Bi,Sb)${}_2$Te${}_3$-type topological insulator, via the Bloembergen-Rowland interaction, magnetic ordering in monolayer Cr${}_2$Te${}_3$ is favorably enhanced, displaying an increased Curie temperature [3]. Combining advanced scanning tunneling microscopy, magnetic force microscopy, transmission electron microscopy, depth-sensitive polarized neutron reflectometry, magnetotransport and ab initio simulation, Cr${}_2$Te${}_3$ has been established as a far-reaching platform for further investigating the marriage of magnetism and topology, in both real and reciprocal spaces. These findings provide new perspectives to the magnetic topological materials in general, that are topical for the future development of topological spintronics.

References
[1] H. Chi and J. S. Moodera, "Progress and prospects in the quantum anomalous Hall effect", APL Mater. 10, 090903 (2022). https://doi.org/10.1063/5.0100989
[2] H. Chi, Y. Ou, T. B. Eldred, W. Gao, S. Kwon, J. Murray, M. Dreyer, R. E. Butera, . . . J. S. Moodera, "Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride", Nat. Commun. 14, 3222 (2023). https://doi.org/10.1038/s41467-023-38995-4
[3] Y. Ou, M. Mirzhalilov, N. M. Nemes, J. L. Martinez, M. Rocci, A. Akey, W. Ge, D. Suri, . . . H. Chi, "Enhanced Ferromagnetism in Monolayer Cr${}_2$Te${}_3$ via Topological Insulator Coupling", arXiv:2312.15028 (2024). https://doi.org/10.48550/arXiv.2312.15028