Universal behavior of the bosonic metallic ground state in a two-dimensional superconductor

AbstractAnomalous metallic behavior, marked by a saturating finite resistivity much lower than the Drude estimate, has been observed in a wide range of two-dimensional superconductors. Utilizing the electrostatically gated LaAlO3/SrTiO3 interface as a versatile platform for superconductor-metal quantum phase transitions, we probe variations in the gate, magnetic field, and temperature to construct a phase diagram crossing from superconductor, anomalous metal, vortex liquid, to the Drude metal state, combining longitudinal and Hall resistivity measurements. We find that the anomalous metal phases induced by gating and magnetic field, although differing in symmetry, are connected in the phase diagram and exhibit similar magnetic field response approaching zero temperature. Namely, within a finite regime of the anomalous metal state, the longitudinal resistivity linearly depends on the field while the Hall resistivity diminishes, indicating an emergent particle-hole symmetry. The universal behavior highlights the uniqueness of the quantum bosonic metallic state, distinct from bosonic insulators and vortex liquids.

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Robust anomalous metallic states and vestiges of self-duality in two-dimensional granular In-InOx composites

npj Quantum Materials ◽

10.1038/s41535-021-00329-2 ◽

2021 ◽

Vol 6 (1) ◽

Author(s):

Xinyang Zhang ◽

Bar Hen ◽

Alexander Palevski ◽

Aharon Kapitulnik

Keyword(s):

Magnetic Field ◽

Metallic Phase ◽

Broadband Noise ◽

Two Dimensional ◽

Conventional Theory ◽

Logarithmic Divergence ◽

Self Duality ◽

Low Field ◽

Wide Range ◽

Low Temperature Resistance

AbstractMany experiments investigating magnetic-field tuned superconductor-insulator transition (H-SIT) often exhibit low-temperature resistance saturation, which is interpreted as an anomalous metallic phase emerging from a ‘failed superconductor’, thus challenging conventional theory. Here we study a random granular array of indium islands grown on a gateable layer of indium-oxide. By tuning the intergrain couplings, we reveal a wide range of magnetic fields where resistance saturation is observed, under conditions of careful electromagnetic filtering and within a wide range of linear response. Exposure to external broadband noise or microwave radiation is shown to strengthen the tendency of superconductivity, where at low field a global superconducting phase is restored. Increasing magnetic field unveils an ‘avoided H-SIT’ that exhibits granularity-induced logarithmic divergence of the resistance/conductance above/below that transition, pointing to possible vestiges of the original emergent duality observed in a true H-SIT. We conclude that anomalous metallic phase is intimately associated with inherent inhomogeneities, exhibiting robust behavior at attainable temperatures for strongly granular two-dimensional systems.

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Thermal Robustness of Entanglement in a Dissipative Two-Dimensional Spin System in an Inhomogeneous Magnetic Field

Entropy ◽

10.3390/e23081066 ◽

2021 ◽

Vol 23 (8) ◽

pp. 1066

Author(s):

Gehad Sadiek ◽

Samaher Almalki

Keyword(s):

Magnetic Field ◽

Steady State ◽

Nearest Neighbor ◽

Quantum Phase Transitions ◽

Inhomogeneous Magnetic Field ◽

Steady States ◽

Inhomogeneous Field ◽

Spin States ◽

Two Dimensional ◽

Spin Lattice

Recently new novel magnetic phases were shown to exist in the asymptotic steady states of spin systems coupled to dissipative environments at zero temperature. Tuning the different system parameters led to quantum phase transitions among those states. We study, here, a finite two-dimensional Heisenberg triangular spin lattice coupled to a dissipative Markovian Lindblad environment at finite temperature. We show how applying an inhomogeneous magnetic field to the system at different degrees of anisotropy may significantly affect the spin states, and the entanglement properties and distribution among the spins in the asymptotic steady state of the system. In particular, applying an inhomogeneous field with an inward (growing) gradient toward the central spin is found to considerably enhance the nearest neighbor entanglement and its robustness against the thermal dissipative decay effect in the completely anisotropic (Ising) system, whereas the beyond nearest neighbor ones vanish entirely. The spins of the system in this case reach different steady states depending on their positions in the lattice. However, the inhomogeneity of the field shows no effect on the entanglement in the completely isotropic (XXX) system, which vanishes asymptotically under any system configuration and the spins relax to a separable (disentangled) steady state with all the spins reaching a common spin state. Interestingly, applying the same field to a partially anisotropic (XYZ) system does not just enhance the nearest neighbor entanglements and their thermal robustness but all the long-range ones as well, while the spins relax asymptotically to very distinguished spin states, which is a sign of a critical behavior taking place at this combination of system anisotropy and field inhomogeneity.

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Anisotropy-temperature phase diagram for the two-dimensional dipolar Heisenberg model with and without magnetic field

Physical Review B ◽

10.1103/physrevb.100.094407 ◽

2019 ◽

Vol 100 (9) ◽

Cited By ~ 1

Author(s):

Hisato Komatsu ◽

Yoshihiko Nonomura ◽

Masamichi Nishino

Keyword(s):

Magnetic Field ◽

Phase Diagram ◽

Heisenberg Model ◽

Temperature Phase ◽

Two Dimensional ◽

Temperature Phase Diagram

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Phase diagram for large two-dimensional bipolarons in a magnetic field

Physical Review B ◽

10.1103/physrevb.57.10569 ◽

1998 ◽

Vol 57 (17) ◽

pp. 10569-10575 ◽

Cited By ~ 6

Author(s):

Wilson B. da Costa ◽

François M. Peeters

Keyword(s):

Magnetic Field ◽

Phase Diagram ◽

Two Dimensional

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The Strange Metal State of the Electron-Doped Cuprates

Annual Review of Condensed Matter Physics ◽

10.1146/annurev-conmatphys-031119-050558 ◽

2020 ◽

Vol 11 (1) ◽

pp. 213-229 ◽

Cited By ~ 5

Author(s):

Richard L. Greene ◽

Pampa R. Mandal ◽

Nicholas R. Poniatowski ◽

Tarapada Sarkar

Keyword(s):

Phase Diagram ◽

High Temperature ◽

Copper Oxide ◽

Normal State ◽

Cuprate Superconductors ◽

Condensed Matter ◽

Metallic State ◽

Final Theory ◽

Physics Community ◽

Metal State

An understanding of the high-temperature copper oxide (cuprate) superconductors has eluded the physics community for over thirty years and represents one of the greatest unsolved problems in condensed matter physics. Particularly enigmatic is the normal state from which superconductivity emerges, so much so that this phase has been dubbed a “strange metal.” In this article, we review recent research into this strange metallic state as realized in the electron-doped cuprates with a focus on their transport properties. The electron-doped compounds differ in several ways from their more thoroughly studied hole-doped counterparts, and understanding these asymmetries of the phase diagram may prove crucial to developing a final theory of the cuprates. Most of the experimental results discussed in this review have yet to be explained and remain an outstanding challenge for theory.

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A Two-Dimensional Spectrometer for Solar Observation and its recent modifications

International Astronomical Union Colloquium ◽

10.1017/s0252921100022922 ◽

1995 ◽

Vol 149 ◽

pp. 188-192

Author(s):

Cornelia Bendlin

Keyword(s):

Magnetic Field ◽

Solar Magnetic Field ◽

Narrow Band ◽

Solar Observation ◽

Two Dimensional ◽

Vacuum Tower ◽

Additional Information ◽

Combined Use ◽

Wide Range ◽

Fabry Perot

AbstractThe instrument presented here is based on the combined use of a Universal Birefringent Filter (UBF) and a Fabry-Perot Interferometer (FPI) to obtain narrow-band filtergrams with a CCD. Scanning through a Fraunhofer line with a sufficient number of wavelength settings is accomplished within a few seconds by tuning only the FPI. The two-dimensional spectrometer in the German Vacuum Tower Telescope (VTT)/Tenerife was used to take observations of high spatial, spectral, and temporal resolution, yielding a wide range of results. Since recently, additional information on the solar magnetic field is obtained with it.

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Mean-field phase diagram of two-dimensional electrons with disorder in a weak magnetic field

Physical Review B ◽

10.1103/physrevb.68.155328 ◽

2003 ◽

Vol 68 (15) ◽

Cited By ~ 2

Author(s):

I. S. Burmistrov ◽

M. A. Baranov

Keyword(s):

Magnetic Field ◽

Phase Diagram ◽

Weak Magnetic Field ◽

Mean Field ◽

Two Dimensional ◽

Field Phase

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Phase Transition in 2D Anisotropic Ising Model with Next-Nearest Neighbor Interactions in a Magnetic Field

SPIN ◽

10.1142/s2010324718500108 ◽

2018 ◽

Vol 08 (03) ◽

pp. 1850010

Author(s):

D. Farsal ◽

M. Badia ◽

M. Bennai

Keyword(s):

Magnetic Field ◽

Phase Transition ◽

Phase Diagram ◽

Monte Carlo ◽

Magnetic Susceptibility ◽

Critical Temperature ◽

Ising Model ◽

Nearest Neighbor ◽

Two Dimensional ◽

The Magnetic Field

The critical behavior at the phase transition of the ferromagnetic two-dimensional anisotropic Ising model with next-nearest neighbor (NNN) couplings in the presence of the field is determined using mainly Monte Carlo (MC) method. This method is used to investigate the phase diagram of the model and to verify the existence of a divergence at null temperature which often appears in two-dimensional systems. We analyze also the influence of the report of the NNN interactions [Formula: see text] and the magnetic field [Formula: see text] on the critical temperature of the system, and we show that the critical temperature depends on the magnetic field for positive values of the interaction. Finally, we have investigated other thermodynamical qualities such as the magnetic susceptibility [Formula: see text]. It has been shown that their thermal behavior depends qualitatively and quantitatively on the strength of NNN interactions and the magnetic field.

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