Superconductivity in the high-pressure tetragonal phase of UTe₂.
- 1Department of Physics, University of California San Diego, La Jolla, CA 92903.
- 2Department of Chemistry, Michigan State University, East Lansing, MI 48824.
Abstract
Electrical transport and magnetic measurements have been made on UTe₂ under pressure P up to ~16 GPa to determine the superconducting transition temperature Tc vs. P phase diagram in the high-pressure tetragonal phase. Superconductivity emerges near ~5 GPa, coincident with the orthorhombic-tetragonal phase transition; in the tetragonal phase, Tc reaches a maximum value of ~4 K at 6 GPa and then decreases with P and appears to vanish near 18 GPa. Tetragonal UTe₂ has a relatively small upper critical field Hc2(0) ≈ 1.2 T at 5.3 GPa, smaller than the Pauli paramagnetic limit, and is orbitally limited with a coherence length ξtetra ≈ 16.5 nm. This small value of Hc2(0) favors more conventional superconductivity; in contrast, the large values of Hc2(T) for orthorhombic UTe₂ exceed the Pauli paramagnetic limit in all three crystallographic directions and have been attributed to unconventional superconductivity, widely believed to involve spin-triplet pairing. The temperature-pressure phase diagram of UTe₂ shows a striking dichotomy: a narrow, fragile, unconventional superconducting region in the orthorhombic phase vs. a broad, robust, and more conventional superconducting dome in the tetragonal phase. This dichotomy is consistent with the proposal that U-dimers, present (absent) in the orthorhombic (tetragonal) phase, may play a role in spin-triplet superconductivity of orthorhombic UTe₂. In the tetragonal phase, the normal-state electrical resistivity ρ(T) exhibits metallic behavior with a "knee" at 200 to 240 K that depends weakly on P and most likely marks the onset of a transition to a magnetically ordered phase that coexists with superconductivity.
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BibTeX
@article{deng2026superconductivity,
title = {{Superconductivity in the high-pressure tetragonal phase of UTe₂.}},
author = {Yuhang Deng and Gabriel Mee and Tyler Wannamaker and Keke Feng and Mingyu Xu and Weiwei Xie and M Brian Maple},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {2026},
month = oct,
doi = {10.1073/pnas.2621369123},
url = {https://europepmc.org/article/MED/42879485},
note = {CC BY},
}
RIS
TY - JOUR
TI - Superconductivity in the high-pressure tetragonal phase of UTe₂.
AU - Yuhang Deng
AU - Gabriel Mee
AU - Tyler Wannamaker
AU - Keke Feng
AU - Mingyu Xu
AU - Weiwei Xie
AU - M Brian Maple
PY - 2026
DA - 2026/10/15
JO - Proceedings of the National Academy of Sciences of the United States of America
DO - 10.1073/pnas.2621369123
UR - https://europepmc.org/article/MED/42879485
AB - Electrical transport and magnetic measurements have been made on UTe₂ under pressure P up to ~16 GPa to determine the superconducting transition temperature Tc vs. P phase diagram in the high-pressure tetragonal phase. Superconductivity emerges near ~5 GPa, coincident with the orthorhombic-tetragonal phase transition; in the tetragonal phase, Tc reaches a maximum value of ~4 K at 6 GPa and then decreases with P and appears to vanish near 18 GPa. Tetragonal UTe₂ has a relatively small upper critical field Hc2(0) ≈ 1.2 T at 5.3 GPa, smaller than the Pauli paramagnetic limit, and is orbitally limited with a coherence length ξtetra ≈ 16.5 nm. This small value of Hc2(0) favors more conventional superconductivity; in contrast, the large values of Hc2(T) for orthorhombic UTe₂ exceed the Pauli paramagnetic limit in all three crystallographic directions and have been attributed to unconventional superconductivity, widely believed to involve spin-triplet pairing. The temperature-pressure phase diagram of UTe₂ shows a striking dichotomy: a narrow, fragile, unconventional superconducting region in the orthorhombic phase vs. a broad, robust, and more conventional superconducting dome in the tetragonal phase. This dichotomy is consistent with the proposal that U-dimers, present (absent) in the orthorhombic (tetragonal) phase, may play a role in spin-triplet superconductivity of orthorhombic UTe₂. In the tetragonal phase, the normal-state electrical resistivity ρ(T) exhibits metallic behavior with a "knee" at 200 to 240 K that depends weakly on P and most likely marks the onset of a transition to a magnetically ordered phase that coexists with superconductivity.
SN - 0027-8424
SN - 1091-6490
ER -