Ambient-pressure   NMR in URu2Si2: internal-field anisotropy

Bernal, O. O.; Moroz, Michael; Lukefahr, H. G.; MacLaughlin, D. E.; Mydosh, J. A.; Menovsky, A.A.; Ortíz, César

doi:10.1016/j.jmmm.2003.11.159

Cited by 11 publications

(12 citation statements)

References 9 publications

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“…Amplitude fluctuations of the hastatic order parameter are needed to describe the incoherent Fermi liquid observed to develop at temperatures well above T HO in optical, tunneling and thermodynamic measurements, [38][39][40]56 and they will reduce the transverse moment. We note that various probes, including X-rays, µ-spin resonance and NMR 66,67,75,76 have consistently detected basal plane fields of order 0.5G, consistent with the presence of a tiny in-plane moment.…”

Section: B Experimental Constraints and More Testssupporting

confidence: 54%

Hastatic order inURu2Si2: Hybridization with a twist

2015

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The broken symmetry that develops below 17.5K in the heavy fermion compound URu2Si2 has long eluded identification. Here we argue that the recent observation of Ising quasiparticles in URu2Si2 results from a spinor hybridization order parameter that breaks double time-reversal symmetry by mixing states of integer and half-integer spin. Such "hastatic order" (hasta:[Latin]spear ) hybridizes Kramers conduction electrons with Ising, non-Kramers 5f 2 states of the uranium atoms to produce Ising quasiparticles. The development of a spinorial hybridization at 17.5K accounts for both the large entropy of condensation and the magnetic anomaly observed in torque magnetometry. This paper develops the theory of hastatic order in detail, providing the mathematical development of its key concepts. Hastatic order predicts a tiny transverse moment in the conduction sea, a collosal Ising anisotropy in the nonlinear susceptibility anomaly and a resonant energy-dependent nematicity in the tunneling density of states.

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Section: B Experimental Constraints and More Testssupporting

confidence: 54%

Hastatic order inURu2Si2: Hybridization with a twist

2015

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“…We revisit the tetragonal symmetry breaking to find three relevant couplings with vastly different microscopic magnitudes that reconcile the experimental literature, and show that weak in-plane anisotropy leads to soft transverse fluctuations that couple linearly to random strains. These lead to an Imry-Ma-like loss of tetragonal symmetry breaking beyond a small critical disorder that explains why neutrons find no basal plane moments, even as µSR and NMR see disordered local fields [42,43]. The fluctuations can be stiffened by external strain or transverse magnetic fields, predicting an additional ordering transition where the transverse moments develop that should be observable in neutrons or elastoresistivity under applied strain or large transverse fields.…”

Section: Introductionmentioning

confidence: 99%

Signatures of spinorial order in URu$_2$Si$_2$: Landau-Ginzburg theory of hastatic order

Kornjača,

Flint

2020

Preprint

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The hidden order in URu 2 Si 2 remains a compelling mystery after more than thirty years, with the order parameter still unidentified. One intriguing proposal for the phase has been hastatic order: a symmetry breaking heavy Fermi liquid with a spinorial hybridization that breaks both single and double time-reversal symmetry. Hastatic order is the first spinorial, rather than vectorial order in materials, but previous work has not yet found direct consequences of the spinorial nature. In this paper, we revisit the hastatic proposal within Landau-Ginzburg theory. Rather than a single spinorial order parameter breaking double-time-reversal symmetry, we find two gauge invariant vectorial orders: the expected composite order with on-site moments, and a new quantity capturing symmetries broken solely by the spinorial nature. We address the effect of fluctuations and disorder on the tetragonal symmetry breaking, explaining the absence of in-plane moments in URu 2 Si 2 and predicting a new transition in transverse field.

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“…Recent high-resolution experiments [61][62][63] have failed to observe a transverse moment of this magnitude, and have placed a bound µ ⊥ < 0.0011µ B on the ordered transverse moment of the uranium ions. Paradoxically various other probes including X-rays, µ-spin resonance and NMR [64][65][66][67] have detected the presence of static basal moments on the order of 0.005µ B that would be consistent with a more integral valent scenario for the U ions.…”

Section: Discussion Of Recent Experimentswith Specific Requestsmentioning

confidence: 99%

Hidden order in URu₂Si₂

Mydosh

2014

Philosophical Magazine

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The observation of Ising quasiparticles is a signatory feature of the hidden order phase of URu2Si2. In this paper we discuss its nature and the strong constraints it places on current theories of the hidden order. In the hastatic theory such anisotropic quasiparticles are naturally described described by resonant scattering between half-integer spin conduction electrons and integer-spin Ising moments. The hybridization that mixes states of different Kramers parity is spinorial; its role as an symmetry-breaking order parameter is consistent with optical and tunnelling probes that indicate its sudden development at the hidden order transition. We discuss the microscopic origin of hastatic order, identifying it as a fractionalization of three body bound-states into integer spin fermions and half-integer spin bosons. After reviewing key features of hastatic order and their broader implications, we discuss our predictions for experiment and recent measurements. We end with challenges both for hastatic order and more generally for any theory of the hidden order state in URu2Si2 .

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Ambient-pressure NMR in URu2Si2: internal-field anisotropy

Cited by 11 publications

References 9 publications

Hastatic order inURu2Si2: Hybridization with a twist

Hastatic order inURu2Si2: Hybridization with a twist

Signatures of spinorial order in URu$_2$Si$_2$: Landau-Ginzburg theory of hastatic order

Hidden order in URu₂Si₂

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Ambient-pressure NMR in URu2Si2: internal-field anisotropy

Cited by 11 publications

References 9 publications

Hastatic order inURu2Si2: Hybridization with a twist

Hastatic order inURu2Si2: Hybridization with a twist

Signatures of spinorial order in URu$_2$Si$_2$: Landau-Ginzburg theory of hastatic order

Hidden order in URu2Si2

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Product

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About

Hidden order in URu₂Si₂