Metastable phase of UTe₂ formed under high pressure above 5 GPa

Journal Article · Mon Nov 07 00:00:00 EST 2022 · Physical Review Materials

DOI:https://doi.org/10.1103/physrevmaterials.6.114801· OSTI ID:1905569

Huston, Larissa Qian  ^[1]; Popov, Dmitry Y. ^[2]; Weiland, Ashley Corene  ^[1]; Bordelon, Mitchell M.  ^[1]; Rosa, Priscila F. S.  ^[1]; Rowland II, Richard Lee  ^[1]; Scott, Brian Lindley  ^[1]; Shen, Guoyin ^[2]; Park, Changyong  ^[2]; Moss, Eric Kauffman  ^[1]; Thomas, Sean Michael  ^[1]; Thompson, Joe David  ^[1]; Sturtevant, Blake T.  ^[1]; Bauer, Eric Dietzgen  ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States)

Uranium ditelluride (UTe₂) has attracted recent interest due to its unique superconducting properties, which include the potential for a topological odd-parity superconducting state. Recently, ac-calorimetry measurements under pressure indicate a change in the ground state of UTe₂ from superconducting to antiferromagnetic at 1.4 GPa. In this work, we investigate the effect of pressure on the crystal structure of UTe₂ up to 25 GPa at room temperature using x-ray diffraction. We find that UTe₂, which at ambient conditions has an orthorhombic (Immm) structure, transforms to a body-centered tetragonal (I4/mmm) structure at 5 GPa in a quasihydrostatic neon (Ne) pressure-transmitting medium. In the absence of a pressure-transmitting medium, this transformation occurs between 5 and 8 GPa. The data were fit with a third-order Birch-Murnaghan equation of state resulting in values of B₀ = 46.0 ± 0.6 GPa , B' = 9.3 ± 0.5 (no pressure medium), and B₀ = 42.5 ± 2.0 GPa , B' = 9.3 (fixed) (neon pressure medium) for the Immm phase. For the I4/mmm phase, B₀ = 78.9 ± 0.5 GPa GPa and B' = 4.2 ± 0.1 (no pressure-transmitting medium), and B₀ = 70.0 ± 1.1 GPa and B' = 4.1 ± 0.2 (neon pressure medium). The high-pressure tetragonal phase is retained after decompression to ambient pressure, with approximately 30% remaining after 2 days. We argue that the observed phase transition into a higher-symmetry structure at P ~ 5 GPa (orthorhombic to tetragonal) is accompanied by an increase in the shortest distance between uranium atoms from 3.6 Å (orthorhombic) to 3.9 Å (tetragonal), which suggests localization of the 5ƒ electrons, albeit with a 10.7% decrease in volume.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC02-06CH11357; 89233218CNA000001
• OSTI ID: 1905569
• Alternate ID(s): OSTI ID: 2008282
• Report Number(s): LA-UR-22-28677; 179974; TRN: US2311836
• Journal Information: Physical Review Materials, Vol. 6, Issue 11; ISSN 2475-9953
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
high-pressure studies
Kondo effect
structural properties
unconventional superconductors
x-ray powder diffraction