Searching for hidden phases born of a quantum spin liquid

Abstract

In this dissertation, we address the hidden phases that are proximate to quantum spin liquids (QSL). QSLs are quantum mechanically disordered phases of matter in magnetic materials, and have been of a great interest as exotic phases whose paradigm lies beyond the Landau’s symmetry breaking theory. In particular, the understanding of QSL characters, such as topological order, quantum number fractionalization, and emergent gauge structure, as well as the experimental detection of quantum entanglement in the ground state wave function, are important issues in condensed matter physics. We have investigated how to control the emergent gauge in pyrochlore U(1) QSL and searched new exotic phases, e.g. by applying external fields. The QSL phases discovered in this process turn out to exhibit unique properties such as topological heat transport, multipolar order, or structural domain patterns.