Date of Graduation

12-2017

Document Type

Thesis

Degree Name

Master of Science in Physics (MS)

Degree Level

Graduate

Department

Physics

Advisor

Salvador Barraza-Lopez

Committee Member

Suredra Singh

Second Committee Member

Hugh Churchill

Keywords

Monolayer, Multiferroicity, SnO Monolayers, Structural Degenarcies, Two-dimensional Phase Transition

Abstract

Chalcogen-based layered superconductors with a litharge structure such as FeS and FeSe mono-layers undergo structural and superconducting phase transitions that are tunable by doping. Representing another material platform with a litharge structure but without valence d-electrons, SnO monolayers also display a structural ground state with a degenerate rectangular unit cell at zero temperature and a charge-tunable energy barrier that leads to a thermally-controllable structural phase change. Doped SnO monolayers with rectangular degenerate unit cells give rise to two-dimensional multiferroicity. Their two-dimensional elastic energy landscape adopts a basic analytic expression that is employed to discuss this structural transition. The results contained in this thesis increase our intuition on two-dimensional phase transitions and their effects on the properties of two-dimensional atomic materials with structural degeneracies.