GW calculations for Co2MnSi

Student thesis: Master's ThesisMaster of Science (MSc)

Abstract

The state-of-the-art GW approximation method has been used to discover the cor-
relations of electrons in full Heusler alloy Co 2 MnSi. Co 2 MnSi has been studied as
a candidate of spintronics devices due to its 100% spin-polarization at Fermi level.
However, Co 2 MnSi with transition metals also plays host to strong electron cor-
relations which result in the difficulties of theoretical prediction with traditional
DFT methods. Previous study shows that the Fermi surfaces of DFT-LSDA cal-
culation are different from the Compton scattering experiments. The GW method
that is based on Hedin’s equations is designed to describe the self-energy which
contains the complex exchange-correlation interactions beyond the DFT. A high-
accuracy single-shot GW calculation is performed to reconstruct the Fermi surfaces
of Co 2 MnSi. From the results of GW calculation, the correlation problems have
been significantly corrected which give a better description of the Fermi surfaces
of Co 2 MnSi. A combination of the GW method and the high-resolution Compton
scattering technique provides a way to investigate the Fermi surfaces of strongly-
correlated materials.
Date of Award28 Nov 2019
Original languageEnglish
Awarding Institution
  • The University of Bristol
SupervisorStephen B Dugdale (Supervisor)

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