Correlation effects on coupled electronic and structural properties of doped rare-earth trihydrides
Year: 2025
Type: article
Abstract: Rare-earth trihydride ($R{\mathrm{H}}_{3}$) compounds exhibit intriguing coupled electronic and structural properties as a function of doping, hydrogen vacancies, and thermodynamic conditions. Theoretical studies of these materials typically rely on density functional theory (DFT), including the use of small supercells that may underestimate strong correlation effects and structural distortions which in turn may influence their metallicity. Here, we elucidate the roles of lattice distortions and correlation effects on the electronic properties of pristine and doped $R{\mathrm{H}}_{3}$ compounds by adopting $\mathrm{DFT}+\mathrm{U}$ and quantum Monte Carlo (QMC) methods. Linear-response constrained DFT (LR-cDFT) methods find Hubbard U $\ensuremath{\approx}2$ eV for ${R}_{d}$ orbitals and $\mathrm{U}\ensuremath{\approx}6$ eV for ${\mathrm{H}}_{s}/{\mathrm{N}}_{p}/{\mathrm{O}}_{p}$ orbitals. The small U on ${\mathrm{Lu}}_{d}$ orbitals is consistent with QMC calculations on ${\mathrm{LuH}}_{3}$ and ${\mathrm{LuH}}_{2.875}{\mathrm{N}}_{0.125}$. In pure face-centered-cubic (FCC) $R{\mathrm{H}}_{3}$ ($R=\mathrm{Lu},\mathrm{Y}$) compounds, neither DFT nor $\mathrm{DFT}+\mathrm{U}$ with the self-consistently determined U is enough to create a band gap, however a supercell with hydrogen distortions creates a small gap whose magnitude increases when performing $\mathrm{DFT}+\mathrm{U}$ with self-consistently determined U values. Correlation effects, in turn, have a moderate influence on the coupled structural and electronic properties of doped $R{\mathrm{H}}_{3}$ compounds and may be important when considering the competition between structural distortions and superconductivity.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: Materials Sciences and Engineering Division, National Science Foundation, U.S. Department of Energy, UT-Battelle, National Energy Research Scientific Computing Center, Office of Science, National Nuclear Security Administration, Division of Materials Research, Basic Energy Sciences, Argonne National Laboratory, Oak Ridge National Laboratory, Lawrence Berkeley National Laboratory
Awards: SI2-SSE: Collaborative Research: Software Framework for Strongly Correlated Materials: from DFT to DMFT, G102163711, G1071216263, G107546177, G1079818582, THE CHICAGO/DOE ALLIANCE CENTER (CDAC)IS DEDICATED TO BASIC RESEARCH, TRAINING, AND TECHNIQUE DEVELOPMENT IN THE STUDY OF MATERIALS IN EXTREME CONDITIONS. THE CENTER HAS ENABLED NUMEROUS ADVANCES IN HIGH P-T SCIENCE, TECHNOLOGY, AND TRAINING SINCE ITS INCEPTION 16 YEARS AGO AS THE CARNEGIE/DOE ALLIANCE CENTER. THESE ADVANCES INCLUDE STUDENT AND POSTDOC-LED SCIENTIFIC DISCOVERIES AND A SUCCESSFUL TRACK RECORD IN TRAINING EARLY CAREER SCIENTISTS FOR WORK IN THE NNSA COMPLEX.
MATERIALS OF INTEREST ENCOMPASS CRYSTALLINE SOLIDS, FLUIDS AND GLASSES, NANOSTRUCTURED TO MESOSTRUCTURED MATERIALS, AND COMPLEX COMPOSITES. CHEMICALLY THESE MATERIALS INCLUDE D- AND F-ELECTRON ELEMENTS AND ALLOYS, LOW-Z MOLECULAR COMPOUNDS, ENERGETIC MATERIALS AND DETONATION PRODUCTS, DENSE GASES, METAL OXIDES AND HYDRIDES, AND CHEMICALLY HETEROGENEOUS SUBSTANCES. CDAC WILL ADVANCE UNDERSTANDING OF THESE STEWARDSHIP-RELATED CLASSES OF MATERIALS IN EXTREME CONDITIONS IN THE FOLLOWING SIX MATERIAL PROPERTY THRUSTS (1) HIGH P-T STRUCTURES AND PHASE RELATIONS; (2) P-V-T EQUATIONS OF STATE; (3) PHONONS, VIBRATIONAL THERMODYNAMICS, AND ELASTICITY; (4) PLASTICITY, YIELD STRENGTH, AND DEFORMATION; (5) ELECTRONIC AND MAGNETIC STRUCTURE AND DYNAMICS; AND (6) HIGH P-T CHEMISTRY. FOR EACH OF THESE ABOVE MATERIALS AND PROPERTIES THRUSTS, CDAC WILL ADDRESS NEW QUESTIONS, INCLUDING THE FOLLOWING:
• HOW CAN WE UNDERSTAND, PREDICT, AND CONTROL MATTER AND MATERIALS TO VERY HIGH COMPRESSIONS?
• WHAT NEW PHYSICS MAY EMERGE IN ‘COLD’ TO ‘WARM’ DENSE MATTER?
• HOW CAN WE ACCURATELY DETERMINE FUNDAMENTAL THERMODYNAMIC PROPERTIES TO VERY HIGH P AND T?
• HOW DO DEFECTS, GRAIN BOUNDARIES, AND INTERFACES RESPOND TO HIGH P-T CONDITIONS AND STRAIN RATES?
• HOW CAN WE BETTER MEASURE TIME-DEPENDENT TRANSFORMATIONS, AND BRIDGE STRAIN-RATE GAPS BETWEEN STATIC, QUASI-STATIC, AND DYNAMIC COMPRESSION?
• CAN WE BETTER DETERMINE STRENGTH, PLASTICITY, AND RHEOLOGY AT VERY HIGH P-T CONDITIONS?
• CAN WE EXPAND THE HIGH P-T SYNTHETIC CHEMISTRY FRONTIER TO PRODUCE NEW, OPTIMIZED MATERIALS?
CDAC WILL ADDRESS THESE QUESTIONS WITH BOTH STATIC AND DYNAMIC COMPRESSION EXPERIMENTS TOGETHER WITH THEORY, MODELING, AND SIMULATION IN CDAC UNIVERSITY LABORATORIES AS WELL AS DOE/SC AND DOE/NNSA FACILITIES. THE WORK WILL BE ENABLED BY CONTINUED ACCESS TO CDAC’S PARTNER SYNCHROTRON RADIATION FACILITIES, HIGH PRESSURE COLLABORATIVE ACCESS TEAM (HPCAT) AT THE ADVANCED PHOTON SOURCE, ARGONNE NATIONAL LABORATORY (ANL) AND THE FRONTIER INFRARED SPECTROSCOPY (FIS) BEAMLINE AT THE NATIONAL SYNCHROTRON LIGHT SOURCE II, BROOKHAVEN NATIONAL LABORATORY (BNL), AS WELL AS OTHER FACILITIES. THE OVERARCHING SCIENTIFIC OUTCOME IS ADVANCING FUNDAMENTAL UNDERSTANDING OF MATERIALS BEHAVIOR IN EXTREME CONDITIONS, WHICH IN TURN WILL LEAD TO IMPROVED UNDERSTANDING OF MATERIALS AGING, PERFORMANCE OF NEWLY MANUFACTURED MATERIALS, MATERIALS IN MULTIPLE EXTREME ENVIRONMENTS, AND THE CREATION OF NEW MATERIALS.
CDAC ENGAGEMENT WITH NNSA PROGRAMS AT ANL AND WITH ITS PARTNER GROUPS IN ILLINOIS WILL BE SIGNIFICANTLY ENHANCED BY ITS MOVE TO THE UNIVERSITY OF ILLINOIS (UIC). CDAC WILL CONTINUE ITS ACTIVE PROGRAM IN EDUCATION AND TRAINING OF NEXT-GENERATION RESEARCHERS FOR STEWARDSHIP SCIENCE. IN SO DOING, CDAC WILL HOST STUDENT WORKSHOPS AND SPONSOR MEETINGS AND SYMPOSIA FOR THE BROADER COMMUNITY. THE CENTER WILL FACILITATE STUDENT ENGAGEMENT WITH NNSA LABORATORIES AND BE A VEHICLE FOR INTRODUCING EARLY CAREER SCIENTISTS TO NNSA LABORATORY PROGRAMS. THE CENTER WILL CONTINUE TO CLOSELY COLLABORATE WITH OTHER ACADEMIC GROUPS, OTHER SSAA AWARDEES, AND NATIONAL LABORATORY SCIENTISTS. CDAC WILL CONTINUE TO LEVERAGE THE SSAA COOPERATIVE AGREEMENT WITH ADDITIONAL GRANTS, WHICH SO FAR HAVE MULTIPLIED BY SEVERAL TIMES THE IMPACT AND INVESTMENT OF NNSA IN THE CENTER. FINALLY, CDAC WILL CONTINUE TO SUPPORT USE OF NNSA FACILITIES, INCLUDING NIF, Z, AND LANSCE, AND FEASIBILITY STUDIES FOR NEXT-GENERATION NNSA FACILITIES., G1143651532, G122673668, G1286236842, G1286251239, G1313983767, G1664757510, G1677143136, G1863003419, G20671849, G2287611682, G2597208992, G2618837358, G262962599, G2638771445, G2710870262, G2900453181, G2976947256, HIGH ENERGY DENSITY QUANTUM MATTER, G30714459, G3075337988, G3083819904, G309446158, G313676650, G3318903820, G3343660, G3589692066, G3967535168, G4038517476, G4158950854, G419881185, G426311843, G42916606, G4501827968, G4713042109, G4907255817, Renewal: Simple Molecular Systems at Ultrahigh Pressures, G498139845, G5076365615, G513797252, G5288847085, G5387317844, G650090426, G6652958823, G6848031779, G6918803902, G7098706596, G7354628648, G7583137537, G969889393, G993149817
OpenAlex ID: W4410496571