Phonon in SrTiO$_3$ under finite electric fields

TL;DR

This paper introduces an efficient density-functional theory method to analyze phonon structures in solids under finite electric fields, revealing unusual properties in SrTiO$_3$ such as giant frequency shifts and dielectric tunability.

Contribution

It presents a novel computational approach to study phonons under electric fields and applies it to SrTiO$_3$, uncovering new physical phenomena.

Findings

Giant phonon frequency shift observed in SrTiO$_3$

Anomalous piezoelectric response detected

Striking dielectric tunability demonstrated

Abstract

We propose an efficient approach within the density-functional theory to determine the phonon structure of infinite solids under finite electric fields. We apply this approach to technological SrTiO$_3$, predicting many unusual properties--including a giant frequency shift, anomalous piezoelectric response, as well as striking dielectric tunability. A microscopic understanding for individual phonon modes under finite electric fields is also provided.