InterPhon: Ab initio Interface Phonon Calculations within a 3D Electronic Structure Framework

TL;DR

InterPhon is an open-source Python package that simplifies ab initio interfacial phonon calculations, enabling efficient analysis of interfacial vibrational properties and structural predictions across various material interfaces.

Contribution

It introduces a flexible, automated framework for calculating interfacial phonons, extending bulk phonon predictions to complex interface systems with reduced computational cost.

Findings

Identified surface reconstructions via imaginary phonon modes.

Revealed vibrational changes due to oxygen adsorption on Cu.

Predicted structural transitions at Si/GaAs interfaces.

Abstract

This work provides the community with an easily executable open-source Python package designed to automize the evaluation of Interfacial Phonons (InterPhon). Its strategy of arbitrarily defining the interfacial region and periodicity alleviates the excessive computational cost in applying ab initio phonon calculations to interfaces and enables efficient extraction of interfacial phonons. InterPhon makes it possible to apply all of the phonon-based predictions that have been available for bulk systems, to interfacial systems. The first example, in which this package was applied to InAs surfaces, demonstrates a systematic structure search for unexplored surface reconstructions, navigated by the imaginary mode of surface phonons. It eventually explains the anisotropic surface vibrations of the polar crystal. The second example, involving oxygen adsorption on Cu, reveals adsorption-induced vibrational change and its contribution to energetic stability. The third example, on a Si/GaAs interface, shows distinct vibrational patterns depending on interfacial structures. It leads to a prediction regarding the structural transition of interfaces and unveils the processing conditions for spontaneous growth of GaAs nanowires on Si. High-level automation in InterPhon will be of great help in elucidating interfacial atomic dynamics and in implementing an automated computational workflow for diverse interfacial systems.