Symmetry Adapted Analysis of Screw Dislocation: Electronic Structure and Carrier Recombination Mechanisms in GaN

TL;DR

This paper introduces a symmetry-based analytical method for screw dislocations in GaN, revealing their impact on electronic structure and recombination, with implications for optoelectronic device efficiency.

Contribution

It develops a rigorous symmetry-adapted analysis framework for screw dislocations, providing new insights into their electronic and optical effects in GaN.

Findings

Dislocation core exhibits a piezoelectric effect that suppresses radiative recombination.

Non-radiative processes dominate over radiative ones in GaN with screw dislocations.

The method establishes symmetry constraints on electronic transitions in dislocated GaN.

Abstract

As fundamental one-dimensional defects, screw dislocations profoundly reshape the energy landscape and carrier dynamics of crystalline materials. By restoring the exact algebra of the screw dislocation group, we unveil the latent symmetry constraints that govern the electronic structure, providing a more rigorous physical picture than the conventional treatments. When applied to GaN, the method yields a band-connectivity constraint and rigorous dipole selection rules for polarization-resolved transitions. Combined with computed Hamiltonian matrix, the approach gives symmetry-filtered radiative and dielectric calculations and reveals a piezoelectrical effect at the dislocation core that strongly suppresses radiative recombination. The pronounced dominance of non-radiative capture over radiative recombination highlights the detrimental impact of screw dislocations on the luminous efficiency of GaN, providing a theoretical foundation for optimizing dislocation-limited optoelectronic devices.