4-year PhD position in Theoretical condensed matter / Computational physics

Topic: Theoretical study of skyrmion states in frustrated antiferromagnetics

 An antisymmetric Dzyaloshinskii-Moriya spin exchange interaction (DMI) can lead to the formation of twisted magnetic structures. These have attracted much interest mainly after the experimental observation of nontrivial magnetic configurations, called magnetic skyrmion lattices, which have potential technological applications [1]. In ferromagnetic (FM) systems, the skyrmion phase arises from the competition between FM interactions and DMI and it is stabilized by a magnetic field and thermal fluctuations. A similar antiferromagnetic (AFM) skyrmion phase has been discovered in the frustrated classical AFM triangular-lattice Heisenberg model in the field not only with DMI [2] but also without DMI due to further neighbor exchange interactions [3].  It has been shown that magnetic frustration can improve stability of the skyrmion phase [4] and that the usage of AFMs in skyrmion-based devices has certain advantages over the implementation of FM magnets [5]. The goal of the proposed research is theoretical search for suitable candidates among frustrated AFMs that would display skyrmion phases with physically and technologically interesting properties.

Literature:

1.N. Romming, C. Hanneken, M. Menzel, J. E. Bickel, B.Wolter, K. von Bergmann, A. Kubetzka, and R. Wiesendanger, Science 341, 636 (2013).

2.H. D. Rosales, D. C. Cabra, and Pierre Pujol, Phys. Rev. B. 92, 214439 (2015)

3.T. Okubo, S. Chung and H. Kawamura, Phys. Rev. Lett. 108, 017206 (2012).

4.H. Y. Yuan, O. Gomonay, and Mathias Kläui, Phys. Rev. B 96, 134415 (2017).

5.J. Barker, O. A. Tretiakov, Phys. Rev. Lett. 116, 147203 (2016); W. Legrand et al., Nature materials 19, 34 (2020).

Contact: prof. Milan Zukovic, PhD. ([email protected])