Erik Sorensen – McMaster University
Title: Ground State Solitons in Kitaev Spin Chains

Abstract: The bond-dependent Ising interaction present in the Kitaev model has recently attracted considerable attention. The attention has mostly focused on the two-dimensional honeycomb lattice version of the Kitaev model where several materials has been identified as potential realizations. However, one can also imagine realizing simpler one-dimensional Kitaev spin chains that still has a surprisingly rich structure. One example is the ferromagnetic material CoNb2O6 which shows signatures of bond dependent interactions.  It is usually assumed that for the Kitaev spin chains the presence of a magnetic field does not lead to any interesting new physics. However, recently we have identified an unusual chiral soliton phase in antiferromagnetic Kitaev chains, appearing when the field is applied in specific directions. The phase is centered around a special point where a two-fold degenerate ground-state can be exactly found. In this talk I will present some of the interesting physics related to the soliton phase for both integer and half-integer spin and discuss a simple variational
picture of the soliton phase.

Speaker Bio: Erik Sorensen is originally from AArhus Denmark. He got his Ph. D. at the University of California, Santa Cruz in Physics in 1992. After UCSC, he spent two years (1992-94) as a postdoc at UBC in the physics department . From British Columbia he moved to Bloomington, Indiana for a second postdoc (1994-96) in the condensed matter theory group. From December 1996 till the fall of 2001, Professor Sorensen worked as a professeur at the Université Paul Sabatier in Toulouse and in the fall of 2001, he joined the department of physics and astronomy at McMaster University. In general, he work in the area of strongly correlated systems, often on low-dimensional models of frustrated magnets and electronic and superconducting systems, often using state of the art computational methods.