Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 72: Poster Session: Correlated Electrons

TT 72.79: Poster

Mittwoch, 14. März 2018, 15:00–19:00, Poster B

Strong electronic correlations: the example of VO₂ — •Elham Khorasani¹, Malte Schüler², Bálint Aradi¹, and Peter Deák¹ — ¹BCCMS, Universität Bremen, Bremen, Germany. — ²Institut für Theoretische Physik, Universität Brememen, Germany.

The metal-insulator transition in VO₂ has been a controversial issue for several decades. It is at the boundary between band theory and many-body physics and forms an important benchmark problem in theoretical solid state physics. To understand the metal-insulator mechanism across the VO₂ in B-phase, GGA+U calculations based on density functional theory have been done. Our results reveal that GGA+U can not predict the proper ground state of VO₂ in the B-phase.

Our study based on static cluster dynamical mean field theory(sC-DMFT), which is proved itself valuable in the M-phase (J. M. Tomczak et .al,J.Phys. Condens Matter, 19, 365206(2007)), did not lead to the experimentally known gap in the insulator VO₂ in B-phase. So, in the next step, in order to elucidate the correlated electronic structure of the B-phase, the full C-DMFT( P. Werner et al, Phys. Rev. Lett., 97, 076405(2006))have been done. Our results for M-phase show that the implementation of Continues-Time Quantum Monte Carlo based on hybridization expansion (CT-Hyb) as a solver makes a sign problem in full C-DMFT.To overcome the sign problem in CT-Hyb , cluster DMFT using exact agonalisation (ED) has been implemented. We compare ED and CT-QMC results for R-phase and explore properties of B-phase using ED.