Study of unconventional topological phase transitions and the associated emergent Dirac fermions in quantum materials
Abstract
One of the central issues in the study of physics is understanding the nature of phases and the mechanism for the transition between different phases. Recently, a new type of phases dubbed topological insulators has come to the fore in the research of condensed matters. In contrast to the ordinary symmetry breaking phases described by the relevant order parameters, a topological phase can be characterized by a topological invariant. Although there has been a great advance in our understanding of topological insulators for past decades, thanks to the great efforts of researchers, relatively less has been known about the mechanism for the phase transition between two insulators having different topological invariants. The main goal of the current research proposal is to construct a general theory describing the quantum phase transitions between topological insulators and provide a unified theoretical framework to understand topological phases and the associated topological quantum phase transitions. Moreover, since a topological phase transition generally accompanies a closing of the bulk energy gap, one can find gapless fermionic excitations at the critical point, which is often described by Dirac fermions with relativistic energy dispersion. In this respect, the quantum critical point for a topological phase transition is a promising venue for searching new emergent fermions with pseudo-relativistic energy dispersion through an accidental band crossing. To unveil the nature of such an emergent Dirac particle at the quantum critical point for a topological phase transition is another goal of this project.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 20, 2018
- Source ID
- W911NF1810137
Entities
People
- Bohm Jung Yang
Organizations
- Army Contracting Command
- Seoul National University
- United States Army