Mechanisms for Sub-Gap Optical Conductivity in Herbertsmithite
Abstract
Recent terahertz conductivity measurements observed low-power-law frequency dependence of optical conduction within the Mott gap of the Kagome lattice spin-liquid candidate Herbertsmithite. We investigate mechanisms for this observed sub-gap conductivity for two possible scenarios in which the ground-state is described by: 1) a U(1) Dirac spin-liquid with emergent fermionic spinons or 2) a nearly critical Z2 spin-liquid in the vicinity of a continuous quantum phase transition to magnetic order. We identify new mechanisms for optical-absorption via magneto-elastic effects and spin- orbit coupling. In addition, for the Dirac spin-liquid scenario, we establish an explicit microscopic origin for previously proposed absorption mechanisms based on slave-particle effective field theory descriptions.
Keywords
Cite
@article{arxiv.1301.3495,
title = {Mechanisms for Sub-Gap Optical Conductivity in Herbertsmithite},
author = {Andrew C. Potter and T. Senthil and Patrick A. Lee},
journal= {arXiv preprint arXiv:1301.3495},
year = {2013}
}
Comments
15 pages, 4 figures; v2 - references updated