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

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.

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

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhuoyu Chen ◽  
Bai Yang Wang ◽  
Adrian G. Swartz ◽  
Hyeok Yoon ◽  
Yasuyuki Hikita ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Quantum Phase Transitions ◽  
Metallic State ◽  
Two Dimensional ◽  
Metallic Behavior ◽  
Universal Behavior ◽  
Hall Resistivity ◽  
Wide Range ◽  
Metal State

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.

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

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.

An experimental investigation of MHD quasi-two-dimensional turbulent shear flows

2002 ◽  
Vol 456 ◽  
pp. 137-159 ◽  
Author(s):  
KARIM MESSADEK ◽  
RENE MOREAU
Keyword(s):  
Magnetic Field ◽  
Energy Transfer ◽  
Turbulent Flow ◽  
Shear Layer ◽  
Electric Current ◽  
Turbulent Shear ◽  
Two Dimensional ◽  
Joule Dissipation ◽  
Layer Width ◽  
Wide Range

An extensive experimental study is carried out to examine the properties of a quasi-two-dimensional MHD turbulent shear flow. Axisymmetric shear of a mercury layer is enforced by the action of a steady vertical magnetic field and a radial horizontal electric current flowing between a ring set of electrodes and a cylindrical wall. This shear layer is unstable, and the properties of the turbulent flow are studied for a wide range of Hartmann (up to 1800) and Reynolds numbers (up to 106). The mean velocity profiles exhibit a turbulent free shear layer, of thickness larger than that predicted by the laminar theory by two orders of magnitude. The profiles yield the expected linear dependence between the total angular momentum and the electric current when the magnetic field is large enough, but demonstrate a systematic deviation when it is moderate (Ha [lsim ] 250). The quasi-two-dimensional turbulence is characterized by an energy transfer towards the large scales, which leads to a relatively small number of large coherent structures. The properties of these structures result from the competition between the energy transfer and the Joule dissipation within the Hartmann layers. In the intermediate range of wavenumbers (k[lscr ] < k < ki, where k[lscr ] is the integral-length-scale wavenumber and ki the injection wavenumber), the energy spectra exhibit a power law close to k−5/3 when the Joule dissipation is weak and close to k−3 when it is significant. The properties of the turbulent flow in this latter regime depend on only one non-dimensional parameter, the ratio (Ha/Re)(l⊥/h)2 (Ha is the Hartmann number, Re the Reynolds number based on the cell radius, l⊥ a typical transverse scale, and h the layer width).

scholarly journals Instability of the two-dimensional metallic phase to a parallel magnetic field

JETP Letters ◽  
1997 ◽  
Vol 65 (12) ◽  
pp. 932-937 ◽  
Author(s):  
V. M. Pudalov ◽  
G. Brunthaler ◽  
A. Prinz ◽  
G. Bauer
Keyword(s):  
Magnetic Field ◽  
Metallic Phase ◽  
Two Dimensional ◽  
Parallel Magnetic Field

scholarly journals Magnetic-field-induced Metallic Phase at Low Temperature in Two-dimensional Superconductors

2015 ◽  
Vol 65 ◽  
pp. 101-104
Author(s):  
E. Murakami ◽  
A. Ochi ◽  
Y. Kawamura ◽  
S. Kaneko ◽  
S. Okuma
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Metallic Phase ◽  
Two Dimensional

scholarly journals Two-dimensional magnetohydrodynamic turbulence in the small magnetic Prandtl number limit

2012 ◽  
Vol 703 ◽  
pp. 85-98 ◽  
Author(s):  
David G. Dritschel ◽  
Steven M. Tobias
Keyword(s):  
Magnetic Field ◽  
Prandtl Number ◽  
Spectral Method ◽  
Two Dimensional ◽  
Mhd Turbulence ◽  
Magnetic Prandtl Number ◽  
Wide Range ◽  
Lagrangian Advection ◽  
Pseudo Spectral Method ◽  
Pseudo Spectral

AbstractIn this paper we introduce a new method for computations of two-dimensional magnetohydrodynamic (MHD) turbulence at low magnetic Prandtl number $\mathit{Pm}= \nu / \eta $. When $\mathit{Pm}\ll 1$, the magnetic field dissipates at a scale much larger than the velocity field. The method we utilize is a novel hybrid contour–spectral method, the ‘combined Lagrangian advection method’, formally to integrate the equations with zero viscous dissipation. The method is compared with a standard pseudo-spectral method for decreasing $\mathit{Pm}$ for the problem of decaying two-dimensional MHD turbulence. The method is shown to agree well for a wide range of imposed magnetic field strengths. Examples of problems for which such a method may prove invaluable are also given.

Breakdown of the anomalous two-dimensional metallic phase in a parallel magnetic field

1998 ◽  
Vol 249-251 ◽  
pp. 697-700 ◽  
Author(s):  
V.M Pudalov ◽  
G Brunthaler ◽  
A Prinz ◽  
G Bauer
Keyword(s):  
Magnetic Field ◽  
Metallic Phase ◽  
Two Dimensional ◽  
Parallel Magnetic Field

Effects of magnetic field on the liquid gallium thermosyphon fluid flow; a numerical study

2019 ◽  
Vol 30 (2) ◽  
pp. 681-703
Author(s):  
Hamid Teimouri ◽  
Amin Behzadmehr
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Liquid Gallium ◽  
Two Dimensional ◽  
Left Wall ◽  
Content Type ◽  
Wide Range

Purpose This paper aims to numerically study the laminar natural convection in a thermosyphon filled with liquid gallium exposed to a constant magnetic field. The left wall of the thermosyphon is at an uniformed hot temperature, whereas the right wall is at a uniform cold temperature. The top and bottom walls are considered to be adiabatic. All walls are electrically insulated. The effects of Hartmann number, in a wide range of Rayleigh number and aspect ratio combinations, on the natural convection throughout the thermosyphon, are investigated and discussed. Furthermore, different forces that influence the natural flow structure are studied. Design/methodology/approach A Fortran code is developed based on the finite volume method to solve the two-dimensional unsteady governing equations. Findings Imposing a magnetic field improves the stability of the fluid flow and thus reduces the Nusselt number. For a given Hartmann and Rayleigh number, there is an optimum aspect ratio for which the average velocity becomes maximum. Research limitations/implications This paper is a two-dimensional investigation. Originality/value To the best of the authors’ knowledge, the effect of the magnetic field on natural convection of liquid gallium in the considered thermosyphon has not been studied numerically in detail. The results of this paper would be helpful in considering the application of the low Prandtl number’s liquid metals in thermosyphon MHD generators and certain cooling devices.

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