Parametrization of LSDA plus U for noncollinear magnetic configurations: Multipolar magnetism in UO2
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
To explore the formation of noncollinear magnetic configurations in materials with strongly correlated electrons, we derive a noncollinear
LSDA
+
U
model involving only one parameter
U
, as opposed to the difference between the Hubbard and Stoner parameters
U
−
J
. Computing
U
in the constrained random phase approximation, we investigate noncollinear magnetism of uranium dioxide
UO
2
and find that the spin-orbit coupling (SOC) stabilizes the
3
k
ordered magnetic ground state. The estimated SOC strength in
UO
2
is as large as 0.73 eV per uranium atom, making spin and orbital degrees of freedom virtually inseparable. Using a multipolar pseudospin Hamiltonian, we show how octupolar and dipole-dipole exchange coupling help establish the
3
k
magnetic ground state with canted ordering of uranium
f
orbitals. The cooperative Jahn-Teller effect does not appear to play a significant part in stabilizing the noncollinear
3
k
state, which has the lowest energy even in an undistorted lattice. The choice of parameter
U
in the
LSDA
+
U
model has a notable quantitative effect on the predicted properties of
UO
2
, in particular on the magnetic exchange interaction and, perhaps trivially, on the band gap: The value of
U
=
3.46
eV
computed fully ab initio delivers the band gap of 2.11 eV in good agreement with experiment, and a balanced account of other pertinent energy scales.
LSDA
+
U
model involving only one parameter
U
, as opposed to the difference between the Hubbard and Stoner parameters
U
−
J
. Computing
U
in the constrained random phase approximation, we investigate noncollinear magnetism of uranium dioxide
UO
2
and find that the spin-orbit coupling (SOC) stabilizes the
3
k
ordered magnetic ground state. The estimated SOC strength in
UO
2
is as large as 0.73 eV per uranium atom, making spin and orbital degrees of freedom virtually inseparable. Using a multipolar pseudospin Hamiltonian, we show how octupolar and dipole-dipole exchange coupling help establish the
3
k
magnetic ground state with canted ordering of uranium
f
orbitals. The cooperative Jahn-Teller effect does not appear to play a significant part in stabilizing the noncollinear
3
k
state, which has the lowest energy even in an undistorted lattice. The choice of parameter
U
in the
LSDA
+
U
model has a notable quantitative effect on the predicted properties of
UO
2
, in particular on the magnetic exchange interaction and, perhaps trivially, on the band gap: The value of
U
=
3.46
eV
computed fully ab initio delivers the band gap of 2.11 eV in good agreement with experiment, and a balanced account of other pertinent energy scales.
Date Issued
2019-08-19
Date Acceptance
2019-08-01
Citation
Physical Review Materials, 2019, 3 (8), pp.1-14
ISSN
2475-9953
Publisher
American Physical Society
Start Page
1
End Page
14
Journal / Book Title
Physical Review Materials
Volume
3
Issue
8
Copyright Statement
©2019 American Physical Society
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000481615400002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Materials Science
DENSITY-FUNCTIONAL THEORY
SPIN-LATTICE INTERACTION
ELECTRONIC-STRUCTURE
NEUTRON-DIFFRACTION
STRUCTURAL STABILITY
MOLECULAR-DYNAMICS
ANTIFERROMAGNETISM
SPECTRA
SYSTEMS
SURFACE
Publication Status
Published
Article Number
ARTN 083802
Date Publish Online
2019-08-19