Regensburg 2016 – scientific programme

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SYES: Symposium Frontiers of Electronic Structure Theory: Focus on Topology and Transport

SYES 6: Frontiers of Electronic Structure Theory: Focus on Topology and Transport IV

SYES 6.4: Talk

Thursday, March 10, 2016, 11:45–12:00, H24

Electronic reconstruction and anomalous Hall conductivity in 3d-oxide honeycomb lattices within the corundum structure — •santu baidya and rossitza pentcheva — Fakultät für Physik and Center of Nanointegration (CENIDE), Universität Duisburg-Essen, 47057 Duisburg

The electronic structure of 3d transition metal oxide honeycomb layers confined in the corundum structure (α-Al₂O₃) along the [0001] direction is investigated using density functional theory including an on-site Coulomb term (GGA+U). While in some cases (e.g. (M₂O₃)/(Al₂O₃)₅, M=Fe, Co, V, Cr, Ni) the confined geometry preserves the magnetic and electronic ground state properties of the corresponding bulk corundum compound M₂O₃, strong deviations from the bulk behavior are observed in the case of Ti₂O₃ and Mn₂O₃ bilayers. Our results indicate a formation of a quasi two-dimensional electron gas with a vertical confinement of ∼5 Å for Ti₂O₃ and ∼8.5 Å for Mn₂O₃. As a function of lateral strain (Ti₂O₃)/(Al₂O₃)₅ undergoes a metal-to-insulator transition associated with a switching of orbital polarization. In the metallic state the Dirac point can be tuned to the Fermi level by variation of the c/a ratio. Including spin-orbit coupling a finite anomalous Hall conductivity is observed in (M₂O₃)/(Al₂O₃)₅ (M=Ti, Mn).