April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)
Symposium Supporters
2024 MRS Spring Meeting
SF02.03.02

Strain Dependence of Phonons in α-Uranium

When and Where

Apr 23, 2024
4:00pm - 4:15pm
Terrace Suite 2, Level 4, Summit

Presenter(s)

Co-Author(s)

Mark Mathis1,Chris Marianetti1

Columbia University1

Abstract

Mark Mathis1,Chris Marianetti1

Columbia University1
The phonons in orthorhombic α-uranium have been well studied due to the charge density wave state, yet a systematic study of the phonons as a function of strain has yet to be accomplished. Here we compute the phonons and anharmonicity in α-uranium using the irreducible derivative method, guaranteeing the highest computational efficiency for a finite displacement method. Various functionals within density functional theory are used to study the change in phonons with respect to the lattice parameters, with particular focus on changes in the soft-modes. Soft phonon modes other than the mode associated with the charge density wave are also found, which have not yet been identified in previous studies. Quartic phonon interactions associated with all soft modes are computed, allowing for the computation of thermal expansion within the Hartree-Fock approximation for phonons. Our findings are compared with existing experimental data.

Keywords

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Symposium Organizers

Edgar Buck, Pacific Northwest National Laboratory
Sarah Hernandez, Los Alamos National Laboratory
David Shuh, Lawrence Berkeley National Laboratory
Evgenia Tereshina-Chitrova, Czech Academy of Sciences

Session Chairs

James Tobin
Angela Wilson

In this Session