arXiv subjects

Jamie M Booth

Publications and source records attributed to Jamie M Booth.

2 recordsLinked to original sources

arXiv2020

A Wilsonian Approach to Crystal Structure Transformations driven by Strong Electron Correlations

Mathematical descriptions of the interplay between strong electron correlations and lattice degrees of freedom are of enormous importance in the development of new devices based on metal oxides such as VO$_{2}$ and the Cuprate superconductors. In this work the physics of tight-binding type electron momentum states interacting with lattice fluctuations is reformulated into an approach based on lattice QCD. Strong electron correlations act as a source for phonons, which are incorporated by using SU(2) bosons acting on neighbouring atomic sites. This allows the system to be described by a Hamiltonian which describes strong interactions between SU(2) Yang-Mills bosons near T$_{c}$ resulting from electron correlations. Monte Carlo and GW calculations show that at low Temperature the electron-electron interactions drive the system into a phase coherent phonon state, breaking the lattice symmetry, and a band gap opens. This formalism is intrinsically able to combine strong-electron correlations with lattice fluctuations in a manner which describes symmetry-breaking structural phase transitions which manifest spin- and charge ordering.

cond-mat.str-el↗

arXiv2016

Correlating the Energetics and Atomic Motions of the Metal-Insulator Transition of M1 Vanadium Dioxide

Materials that undergo reversible metal-insulator transitions are obvious candidates for new generations of devices. For such potential to be realised, the underlying microscopic mechanisms of such transitions must be fully determined. In this work we probe the correlation between the energy landscape and electronic structure of the metal-insulator transition of vanadium dioxide and the atomic motions occurring using first principles calculations and high resolution X-ray diffraction. Calculations find an energy barrier between the high and low temperature phases corresponding to contraction followed by expansion of the distances between vanadium atoms on neighbouring sub-lattices. X-ray diffraction reveals anisotropic strain broadening in the low temperature structure's crystal planes, however only for those with spacings affected by this compression/expansion. GW calculations reveal that traversing this barrier destabilises the bonding/anti-bonding splitting of the low temperature phase. This precise atomic description of the origin of the energy barrier separating the two structures will facilitate more precise control over the transition characteristics for new applications and devices.

cond-mat.mtrl-sci↗