Date of Degree
Condensed Matter Physics | Physics
Ising model; LiHoF4; mean field theory; quantum criticality
In this dissertation, I study the magnetic properties of LiHoF4. Quantum criticality in rare earth ferromagnet LiHoF4 is complicated by the presence of strong crystal field and hyperfine interactions resulting, e.g., in incomplete mode softening reported by Rønnow et al. We construct a systematic framework for treating elementary excitations in this material across the phase diagram. These excitations interpolate between purely electronic, nuclear and lattice modes and exhibit two-types of quantum critical softening, both complete (as anticipated by elementary treatments, see e.g. Sachdev) but also incomplete, in close correspondence with nuclear scattering results.
Ma, Haifu, "Hybridized Criticality and Elementary Excitations in LiHoF4" (2015). CUNY Academic Works.