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Thesis topic proposal
 
László Szunyogh
Spin-spiral states in ultrathin films and nanowires

THESIS TOPIC PROPOSAL

Institute: Budapest University of Technology and Economics
physics
Doctoral School of Physics

Thesis supervisor: László Szunyogh
Location of studies (in Hungarian): Department of Theoretical Physics, Institute of Physics
Abbreviation of location of studies: BME


Description of the research topic:

Many bulk magnets and magnetic thin films exhibit helical or spin-spiral ground states. In the presence of magnetic field, spin spirals can transform to topologically protected whirling textures called magnetic skyrmions, while in nanowires deposited on top of superconductors Majorana bound states can be formed, both of which being prospective hardware elements of quantum information technology. Quantum mechanical (first principles) calculation of the electronic structure of spin-spiral states is possible via the generalized Bloch theorem in case of simultaneous translational and spin-rotational symmetry. Self-consistent calculation of the spin-spiral state is possible only in the non-relativistic limit, while effects of spin-orbit coupling can be accounted for by using perturbation techniques. The PhD student will aquire the use of the spin-spiral code developed in our research group in terms of the multiple scattering Green's-function formalism. As first application, we plan to determine the magnetic ground state of an Fe monolayer on top of Ta(110) for which both recent experiments and previous spin-model studies explored a rather long wave-length spin spiral. A particular goal of the PhD work is to extend the code to infinite on-dimensional wires and perform calculations for magnetic wires in connection to topological superconductivity as proposed in Fe wires on Re(0001) or Mn wires on Nb(110). In addition, we intend to combine this code with the solution of the Bogoliubov - de Gennes equations which will enable to study proximity-induced superconductivity in these systems.

Required language skills: english
Further requirements: 
thorough knowledge in relativistic quantummechanics, theoretical solid state physics and strong motivation for computational research

Number of students who can be accepted: 1

Deadline for application: 2024-05-31


2024. IV. 17.
ODT ülés
Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).

 
All rights reserved © 2007, Hungarian Doctoral Council. Doctoral Council registration number at commissioner for data protection: 02003/0001. Program version: 2.2358 ( 2017. X. 31. )