Regensburg 2019 – scientific programme
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MA: Fachverband Magnetismus
MA 55: Electron theory and micromagnetism
MA 55.4: Talk
Friday, April 5, 2019, 10:15–10:30, H38
Hybridization-switching induced Mott transition in magnetic ABO3 perovskites — •Atanu Paul1, Anamitra Mukherjee2, Indra Dasgupta1, Arun Paramekanti3, and Tanusri Saha-Dasgupta4,5 — 1School of Physical Sciences, Indian Association for the Cultivation of Science, Kolkata, India — 2School of Physical Sciences, National Institute of Science Education and Research, Jatni, India — 3Department of Physics, University of Toronto, Ontario, Canada — 4Department of Condensed Matter Physics and Materials Science, S.N. Bose National Centre for Basic Sciences, Kolkata, India — 5School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Kolkata, India
We propose the concept of "hybridization-switching induced Mott transition" which is relevant to a broad class of magnetic ABO3 perovskite materials including BiNiO3 and PbCrO3 which feature extended 6s orbitals on the A-site cation (Bi or Pb), and A-O covalency induced ligand hole. Using ab initio electronic structure and model Hamiltonian calculations, we show that such systems exhibit a breathing phonon driven A-site to oxygen hybridization-wave instability which conspires with strong correlations on the magnetic B-site transition metal ion (Ni or Cr) to induce an antiferromagnetic Mott insulator. These Mott insulators with active A-site orbitals are shown to undergo a pressure induced antiferromagnetic insulator to ferromagnetic metal transition accompanied by a colossal volume collapse due to ligand hybridization switching.