April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)
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2024 MRS Spring Meeting & Exhibit
SF02.04.01

Ab-Initio Spin-Fluctuation Hamiltonian for Delta-Pu at Finite Temperatures

When and Where

Apr 24, 2024
8:30am - 9:00am
Terrace Suite 2, Level 4, Summit

Presenter(s)

Co-Author(s)

Babak Sadigh1,Kyoung Kweon1,Per Söderlind1,Michael Surh1,Lorin Benedict1,Fei Zhou1

Lawrence Livermore National Lab1

Abstract

Babak Sadigh1,Kyoung Kweon1,Per Söderlind1,Michael Surh1,Lorin Benedict1,Fei Zhou1

Lawrence Livermore National Lab1
Spin/orbital-polarized density functional theory has been used extensively in the past years to explore materials properties of the Pu metal, from its polymorphic phase diagram to energetics of formation and migration of lattice defects and impurities in the various Pu phases. Calculations to date have been conducted using one or other static low-energy spin configuration. The effect of allowing for non-collinear spin/orbital fluctuations is yet largely unexplored. We have thus developed a novel technique that allows for efficient calculations of adiabatic non-collinear spin/orbital excitations within spin-constraint density-functional theory. We use this technique to extensively explore the potential energy landscape of adiabatic spin fluctuations in delta-Pu. Several families of low-energy non-collinear spin configurations are found. We construct an effective Hamiltonian for thermal spin fluctuations in delta-Pu and study its statistical mechanics via Monte Carlo simulations. We report the impact of spin/orbital fluctuations on the structure and magnetic susceptibility of delta-Pu at finite temperatures.<br/><br/>This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Keywords

Pu

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

Najeb Abdul-Jabbar
Sarah Hernandez

In this Session