Condensed Matter Seminars

Quantum spin liquids evade long-range magnetic order down to absolute zero temperature. These anarchic, yet highly entangled states break no symmetry but have remarkable properties such as fractional excitations. In this talk, I will first give an example of spin liquid using  a compass model relevant to recently discovered honeycomb antiferromagnet NaNi2BiO6. Then I will introduce a new model, the dipolar Heisenberg model, motivated by recent experiments on artificial many-spin systems based on interacting dipoles. I will argue that long-range magnetic order can be suppressed by simply tuning the direction of the dipoles using an external field. The classical, semiclassical, and quantum phase diagram of this frustrated spin model will be presented to show an extended region where the ground state is a quantum paramagnet. By comparing to DMRG, I will argue that it is likely a quantum spin liquid.