Talk given by Prof. Mikhail I. Katsnelson Theory of Condensed Matter Institute for Molecules and Materials Radboud University of Nijmegen The Netherlands Abstract: The problem of sp electron magnetism remains a very controversial issue, both theoretically and experimentally. I will review general theoretical aspects of the problem, such as interplay of Stoner (electron-hole) excitations and spin-waves. It turns out that sp magnetic semiconductors can have much higher Curie temperatures than the conventional ones [1]. I will consider defect-induced magnetism in graphene associated with the edges, grain boundaries, vacancies and adatoms [2,3], together with theoretical aspects of a controversial situation with magnetic fullerenes [4]. The ways how to build effective Hubbard model for carbon-based systems will be discussed [5], as well as frustrated magnetism in single-side hydrogenated and fluorinated graphene [6]. The latter systems provide interesting examples of sp electron magnets with well-defined localized magnetic moments and Heisenberg-like magnetism. [1] D. M. Edwards and M. I. Katsnelson, J. Phys.: Cond. Mat. 18, 7209 (2006). [2] M. I. Katsnelson, Graphene: Carbon in Two Dimensions (Cambridge Univ. Press, 2012), Chap. 12. [3] M. A. Akhukov, A. Fasolino, Y. N. Gornostyrev, and M. I. Katsnelson, Phys. Rev. B 85, 115407 (2012). [4] D. W. Boukhvalov and M. I. Katsnelson, Eur. Phys. J B 68, 529 (2009). [5] M. Schueler, M. Roesner, T. O. Wehling, A. I. Lichtenstein, and M. I. Katsnelson, Phys. Rev. Lett. 111, 036601 (2013). [6] A. N. Rudenko, F. J. Keil, M. I. Katsnelson, and A. I. Lichtenstein, Phys. Rev. B 88, 081405(R) (2013).

This event is part of the eventgroup INT Talks

Homepage
https://www.int.kit.edu/events.php

Speaker
Prof. Mikhail I. Katsnelson

University of Nijmegen
http://www.theorphys.science.ru.nl/people/katsnelson/index.php

Organizer
Dr. Igor Gornyi
Institute of Nanotechnology (INT)
Karlsruhe Institute of Technology (KIT)
Eggenstein-Leopoldshafen
Mail: igor gornyi ∂does-not-exist.kit edu

Targetgroup
Interested / Everyone