April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)

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2024 MRS Spring Meeting
QT06.05.03

Irreducible Phonon Interactions and Phonon-Strain Couplings in SrTiO3

When and Where

Apr 24, 2024
11:15am - 11:30am
Room 447, Level 4, Summit

Presenter(s)

Co-Author(s)

Shenwei Wu1,Mark Mathis1,Enda Xiao2,Chris Marianetti1

Columbia University1,National Institute for Materials Science2

Abstract

Shenwei Wu1,Mark Mathis1,Enda Xiao2,Chris Marianetti1

Columbia University1,National Institute for Materials Science2
While strontium titanate (SrTiO<sub>3</sub>) has undergone extensive first-principles analysis, there remains a need for a systematic study of the irreducible phonon interactions to gain a comprehensive understanding of the vibrational Hamiltonian within a given first-principles method. Here we accurately compute cubic, quartic, and selected sextic irreducible phonon interactions, employing both the lone and bundled irreducible derivative approaches. Furthermore, the leading order irreducible strain phonon couplings are computed, yielding a detailed Taylor series of the Born-Oppenheimer potential in terms of displacements and strains. Particular focus is placed on the <i>R</i>-point antiferrodistortive (AFD) soft mode and the Γ-point <i>T<sub>1u</sub></i> manifolds. We demonstrate that the three-fold AFD manifold has a potential that is nearly spherical, while the linear strain coupling mildly favors the experimentally observed tetragonal distortion. The full anharmonic Hamiltonian is solved within the Hartree-Fock approximation for phonons, and the resulting observables are compared to previous similar calculations and experimental data.

Symposium Organizers

Lucas Caretta, Brown University
Yu-Tsun Shao, University of Southern California
Sandhya Susarla, Arizona State University
Y. Eren Suyolcu, Max Planck Institute

Session Chairs

Y. Eren Suyolcu

In this Session