Fermi-surface reconstruction at the metamagnetic high-field transition in uranium mononitride

Hamann, Sandra; Förster, Tobias; Gorbunov, D. I.; König, Markus; Uhlarz, M.; Wosnitza, J.; Helm, Toni

doi:10.1103/physrevb.104.155123

Cited by 5 publications

(5 citation statements)

References 53 publications

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“…Upon decreasing temperature, the metamagnetic transition evolves from a broad anomaly into a sharp first-order type transition. Such an evolution resembles the behavior observed in other heavy-fermion metals with metamagnetism in high fields 35 – 37 . Regarding the hfSC phase, our results are in line with previous reports 12 , 17 .…”

Section: Resultssupporting

confidence: 78%

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Helm,

Kimata,

Sudo

et al. 2024

Nat Commun

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The potential spin-triplet heavy-fermion superconductor UTe2 exhibits signatures of multiple distinct superconducting phases. For field aligned along the b axis, a metamagnetic transition occurs at μ0Hm ≈ 35 T. It is associated with magnetic fluctuations that may be beneficial for the field-reinforced superconductivity surviving up to Hm. Once the field is tilted away from the b towards the c axis, a reentrant superconducting phase emerges just above Hm. In order to better understand this remarkably field-resistant superconducting phase, we conducted magnetic-torque and magnetotransport measurements in pulsed magnetic fields. We determine the record-breaking upper critical field of μ0Hc2 ≈ 73 T and its evolution with angle. Furthermore, the normal-state Hall effect experiences a drastic suppression indicative of a reduced band polarization above Hm in the angular range around 30° caused by a partial compensation between the applied field and an exchange field. This promotes the Jaccarino-Peter effect as a likely mechanism for the reentrant superconductivity above Hm.

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Section: Resultssupporting

confidence: 78%

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Helm,

Kimata,

Sudo

et al. 2024

Nat Commun

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“…Upon decreasing temperature, the metamagnetic transition evolves from a broad second-order into a sharp first-order type transition. Such an evolution resembles behavior observed in other uraniumbased metal with long range magnetic order [36]. We reproduced the overall temperature and field dependence reported previously for UTe 2 [10,26].…”

Section: Magnetic Torque Around the Metamagnetic Transitionsupporting

confidence: 89%

Suppressed magnetic scattering sets conditions for the emergence of 40 T high-field superconductivity in UTe2

Helm

Kimata

Sudo

et al. 2022

Preprint

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The potential spin-triplet heavy-fermion superconductor UTe2 exhibits signatures of multiple distinct superconducting phases. For field aligned along the b axis a metamagnetic transition occurs at μ0Hm ≈ 35 T. It is associated with a spin reorientation inducing magnetic fluctuations that may be beneficial for the field-enhanced superconductivity surviving up to Hm. Once the field is tilted away from the b towards the c axis, a re-entrant superconducting phase emerges just above Hm(θ). However, under pressure this phase detaches from Hm. In order to better understand this remarkably field-resistant phase we investigate magnetic torque and electrical magnetotransport in pulsed magnetic fields. The observed zero-Hall signal evidences the superconducting nature of this distinct high-field phase. We determine its record-breaking upper critical field of μ0Hc2 ≈ 75 T. Furthermore, we provide evidence for a strong angle-dependent reduction of magnetic scattering, likely accompanied by changes in the electronic band structure induced by the tilted field.

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“…In contrast to U 3 O 8 , UN showed an absence of any appreciable signal. It strongly confirms that this material is a bandlike system, as already concluded from both the neutron scattering [34], and ARPES measurements [35], with no evidence for any feature of 5f 2 localized electrons. If anything, the broad peak at ∼1 eV, resembles that from a 5f 3 system.…”

Section: Spin Free Statessupporting

confidence: 85%

“…This conclusion was reinforced later by angle-resolved photoemission experiments [34], which showed 5f states at the Fermi level. More recently, high-field experiments on UN single crystals have been interpreted as arising from the 5f states showing both localized and itinerant characteristics [35,36]. An x-ray diffraction experiment on a UN epitaxial film showed there was no evidence for a lattice distortion at T N , which would be expected if the 5f states were localized, and the AF structure was 1k [37].…”

Section: Introductionmentioning

confidence: 99%

Resonant inelastic x-ray scattering from U₃O₈ and UN

Bright

Harding

et al. 2023

J. Phys.: Condens. Matter

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Resonant inelastic x-ray scattering (RIXS) using an incident energy tuned to the uranium N 4,5 absorption edges is reported from epitaxial films of α-U3O8 and UN. Theory shows that for U3O8 the multiplets associated with a 5f 1 configuration with a ground state of 2 F 5/2 and the excited state of 2 F 7/2 are observed. However, the strong transition predicted at a transfer energy of 1.67 eV is not observed. We assume this is a consequence of the intermediate state lifetime broadening due to interaction with continuum states when the transferred energy exceeds the onset of the continuum in the presence of the core hole. This hypothesis is supported by the results obtained for the 5f-itinerant system UN, where no sharp transitions have been observed, although the broad scattering response centered at ∼ 1 eV is considered a signature of a predominantly 5f 3 configuration in this band-like semi-metallic system. These experiments and theory add important information on these materials, both of which have been investigated since the 1960s, as well as whether RIXS at the uranium N edge can become a valuable tool for actinide research.

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Fermi-surface reconstruction at the metamagnetic high-field transition in uranium mononitride

Cited by 5 publications

References 53 publications

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Suppressed magnetic scattering sets conditions for the emergence of 40 T high-field superconductivity in UTe2

Resonant inelastic x-ray scattering from U₃O₈ and UN

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Fermi-surface reconstruction at the metamagnetic high-field transition in uranium mononitride

Cited by 5 publications

References 53 publications

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

Field-induced compensation of magnetic exchange as the possible origin of reentrant superconductivity in UTe2

﻿Suppressed magnetic scattering sets conditions for the emergence of 40 T high-field superconductivity in UTe2

Resonant inelastic x-ray scattering from U3O8 and UN

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Suppressed magnetic scattering sets conditions for the emergence of 40 T high-field superconductivity in UTe2

Resonant inelastic x-ray scattering from U₃O₈ and UN