Theory of Electron-Phonon-Dislon Interacting System - Toward a Quantized Theory of Dislocations

TL;DR

This paper develops a quantum theoretical framework using 'dislons' to analyze how dislocations affect material properties, enabling comprehensive, parameter-free predictions of electronic, phononic, and other transport phenomena.

Contribution

It introduces a unified quantum dislon theory for dislocation effects, surpassing traditional models by incorporating many-body effects and dynamic strain fields without fitting parameters.

Findings

Derived effective electron and phonon theories incorporating dislocation effects.

Demonstrated the theory's ability to predict transport properties in dislocated materials.

Highlighted advantages over classical and empirical models, including quantum effects and no fitting parameters.

Abstract

We provide a comprehensive theoretical framework to study how crystal dislocations influence the functional properties of materials, based on the idea of quantized dislocation, namely a "dislon". In contrast to previous work on dislons which focused on exotic phenomenology, here we focus on the theoretical structure and computational power. We first provide a pedagogical introduction of the necessity and benefits taking the dislon approach, that why the dislon Hamiltonian takes its current form. Then we study the electron-dislocation and phonon-dislocation scattering problems, using the dislon formalism. Both the effective electron and phonon theories are derived, from which the role of dislocations on electronic and phononic transport properties is computed. Comparing with the traditional dislocation scattering studies which are intrinsically single-particle, low-order perturbation and classical quenched defect in nature, the dislon theory not only allows easy incorporation of quantum many-body effects such as electron correlation, electron-phonon interaction and higher-order scattering events, but also allows proper consideration of dislocation's long-range strain field and the dynamic aspects on equal footing. This means that instead of developing individual model for a specific dislocation scattering problem, the dislon theory allows for the calculation of electronic structure and electrical transport, thermal transport, optical and superconducting properties, etc., under one unified theory. Furthermore, the dislon theory has another advantage over empirical models in that it requires no fitting parameters. The dislon theory could serve as a major computational tool to understand the role of dislocations on multiple materials' functional properties at an unprecedented level of clarity, and may have wide applications in dislocated energy materials.