CM Seminar - Magnetoelectric generation of a Majorana-Fermi surface in Kitaev's honeycomb model

Title: "Magnetoelectric generation of a Majorana-Fermi surface in Kitaev's honeycomb model"

Abstract: "Recently, Kitaev materials have attracted great interest due to their potential to realize a quantum spin liquid ground state which hosts gapless Majorana excitations. In this talk, after a review of the physics of Kitaev materials, I will discuss the effects of static magnetic and electric fields on Kitaev's honeycomb model. Using the electric polarization operator appropriate for Kitaev materials, I will derive the effective Hamiltonian for the emergent Majorana fermions to second-order in both the electric and magnetic fields. While individually each perturbation does not qualitatively alter Kitaev spin liquid, the magneto-electric cross-term induces a finite chemical potential at each Dirac node, generating a Majorana-Fermi surface. I will argue this gapless phase is stable and exhibits typical metallic phenomenology, such as linear in temperature heat capacity and finite, but non-quantized, thermal Hall response. Finally, I will discuss the potential for realization of this, and related, physics in Kitaev materials such as RuCl3."

Bio: "Jeffrey G. Rau is an assistant professor at the University of Windsor working in the field of theoretical condensed matter physics. He received his Ph.D. from the University of Toronto followed by post-doctoral work at the University of Waterloo and the Max Planck Institute for the Physics of Complex Systems in Dresden. His research broadly falls under the heading of quantum magnetism, with a focus on highly frustrated systems with strong anisotropy."