Alladi Ramakrishnan Hall

Low-dimensional frustrated quantum magnets in honeycomb and triangular lattices

Rudra Sekhar Manna

Augsburg University

Frustrated magnetism is one of the growing research interests in condensed matter physics. Theoretically different properties of these frustrated quantum magnets have been put forward a while back, but this field has become more interesting with the evidence of many recent motivating experiments. Frustration leads many different fascinating ground states by the coupling of spin, charge, and lattice degrees of freedom, e.g. Kitaev spin-liquid in spin-orbit coupled honeycomb iridates, spin-liquid in triangular and kagome lattices, valence-bond solid, Mott metal-insulator transition, Mott criticality, superconductivity as a function of temperature, magnetic field, and pressure. First part of my talk, I will discuss results of β-Li2IrO3, a 3D hyper-honeycomb where a spin-liquid state might be realized under hydrostatic pressure although at ambient pressure the material displays a complex antiferromagnetic ordering which is stabilized by the Kitaev interaction. In the second part, Mott insulating quasi-2D organic charge-transfer salts in triangular lattices, a phase transition like behavior in κ-(ET)2Cu2(CN)3 although it is proposed to be a spin-liquid [1] and the critical behavior of the endpoint of the Mott transition in κ-(ET)2Cu[N(CN)2]Cl [2] will be discussed.

[1] R. S. Manna, M. Souza, A. Brühl, J. A. Schlueter, and M. Lang, Phys. Rev. Lett. 104, 016403 (2010).
[2] E. Gati, M. Garst, R. S. Manna, U. Tutsch, B.Wolf, L. Bartosch, H. Schubert, T. Sasaki, J. A. Schlueter, and M. Lang, Sci. Adv. (2016) (in press).