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Lifshitz topological transition in interacting Fermi systems

Presented by: 
J Betouras Loughborough University
Monday 16th September 2013 - 14:45 to 15:15
INI Seminar Room 1
Co-authors: Sam T. Carr (Karsruhe Institute of Technology), Jorge Quintanilla (University of Kent), Sergey Slizovskiy (Loughborough University), Ziyang Meng (Louisiana State University), Kuanshing Chen (Louisiana State University), Mark Jarrell (Louisiana State University), Juana Moreno (Louisiana State University)

Recently, the theory of topological Lifshitz transition has become the focus of much attention in complex materials such as high-Tc superconductors, heavy fermions compounds etc. In this talk, we present three cases of topological Lifshitz transitions involving: (i) A Fermi liquid in two and three dimensions, interacting with short range interactions and exhibiting first order Lifshitz transition due to these interactions. The transition becomes more pronounced in the regime of paramagnons. The motivation for this work is provided by recent experiments on the material NaxCoO2.

(ii) The Hubbard model with negative next nearest neighbor hoping that shows to exhibit Lifshitz transition and a "multimode" quantum criticality associated with it and

(iii) Dipolar fermions in optical lattices where we consider an experimentally realizable two dimensional model of non-interacting chains of spinless fermions weakly coupled via a small inter-chain hopping and a repulsive inter-chain interaction. The phase diagram of this model has a surprising feature: an abrupt change in the Fermi surface as the interaction is increased.

The work at Loughborough has been supported by the Engineering and Physical Science Council.

University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons