Theoretical Physics Colloquium

Frustrated Mott insulators: from quantum spin liquids to superconductors

by Prof. Ross McKenzie (University of Queensland, Australia)

Tuesday, November 12, 2013 from to (Asia/Kolkata)
at Colaba Campus ( AG69 )
Description In a seminal paper, conceived in India and published 26 years ago, P.W. Anderson made a radical proposal that there was an intimate connection between high-Tc superconductivity, spin frustration, and a quantum spin liquid [Resonating Valence Bond (RVB) state] in a Mott insulator [1]. I will discuss how charge transfer salts based on organic molecules such as BEDT-TTF and dmit realise some of Anderson's ideas[2]. Small variations in hydrostatic pressure or in chemical composition reveal a subtle competition between Mott insulating, metallic, and superconducting states. Theoretical studies of the relevant Hubbard and Heisenberg models show how spin frustration is essential to stabilising different quantum spin liquid ground states and RVB superconductors.
[1] P.W. Anderson, Science 235, 1196 (1987).
[2] B.J. Powell and R.H. McKenzie, Reports of Progress in Physics 74, 056501 (2011).