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Dr. Giuseppe Cuono (International Research Centre Magtop, Institute of Physics, Polish Academy of Science, Aleja, Warsaw, Poland)

  • Ferromagnetic coupling in HgTe doped with V and Cr: a route for the quantum anomalous Hall effect

    Dr. Giuseppe Cuono (International Research Centre Magtop, Institute of Physics, Polish Academy of Science, Aleja, Warsaw, Poland)

    Aula T1 - Dipartimento di Fisica "E.R.Caianiello"/DF

Dilute magnetic semiconductors have played a central role in the demonstrating and describing a strong and intricate influence of the sp-d exchange interactions upon effective mass states in semiconductors, paving the way for the rise of dilute ferromagnetic semiconductors [1] and magnetic topological insulators [2,3]. Recently the exchange splittings of magneto-optical spectra in Cd1−xMnxTe and Hg1−xMnxTe have been described [4] and it has been demonstrated that superexchange dominates in magnetic topological insulators [5]. Here we investigate the electronic and magnetic properties of the dilute magnetic semiconductors Cd1−x Crx Te, Hg1−x Crx Te, Cd1−x Vx Te, Hg1−x Vx Te by using a density functional theory approach and we compare to the properties of Cd1−x Mnx Te and Hg1−x Mnx Te. We obtain the band structures of these systems, we study the distortions produced by the Jahn-Teller effect and the spin splitting. We state that spin-orbit coupling, electronic correlations and Jahn-Teller distortions are necessary to open the gap in these compounds. We find that the crystal field strongly depends on correlations. Then, we study the exchange couplings for all considered cases and we find that the coupling is ferromagnetic in case of doping with V, differently from the case of doping with Mn, where we find an antiferromagnetic ground state. The ferromagnetic coupling among V atoms in the insulating phase of topological HgTe can produce the quantum anomalous Hall phase.


[1] T. Dietl and H. Ohno, Rev. Mod. Phys. 86, 187 (2014).
[2] H. Ke, Y. Wang, and Q.-K. Xue, Annu. Rev. Condens. Matter Phys. 9, 329 (2018).
[3] Y. Tokura, K. Yasuda, and A. Tsukazaki, Nat. Rev. Phys. 1, 126 (2019).
[4] C. Autieri, C. ́Sliwa, R. Islam, G. Cuono and T. Dietl, Phys. Rev. B 103, 115209 (2021).
[5] C. ́Sliwa, C. Autieri, J. A. Majewski, and T. Dietl, Phys. Rev. B 104, L220404 (2021).