Direct determination of the temperature of overheated electrons in an insulator

Levinson, T.; Doron, A.; Tamir, Idan; Tewari, Girish C.; Shahar, D.

doi:10.1103/physrevb.94.174204

Cited by 9 publications

(6 citation statements)

References 18 publications

(36 reference statements)

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“…where Γ is the e-ph coupling strength, Ω the sample volume, and the power β ≈ 6, calculated for metals in the dirty limit [36], is found in experiment [34]. The success of this theoretical description [34,37] provides an essential indication that at low T 's the electrons in our disordered a:InO thin-films are decoupled from the phonons. To further investigate the feasibility of aforementioned theoretical possibilities we conducted a low-frequency (f ≤ 1 kHz) noise study.…”

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confidence: 81%

Excessive noise as a test for many-body localization

et al. 2019

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Recent experimental reports suggested the existence of a finite-temperature insulator in the vicinity of the superconductor-insulator transition. The rapid decay of conductivity over a narrow temperature range was theoretically linked to both a finite-temperature transition to a many-bodylocalized state, and to a charge-Berezinskii Kosterlitz Thouless transition. Here we report of lowfrequency noise measurements of such insulators to test for many body localization. We observed a huge enhancement of the low-temperatures noise when exceeding a threshold voltage for nonlinear conductivity and discuss our results in light of the theoretical models. arXiv:1806.09492v2 [cond-mat.str-el]

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confidence: 81%

Excessive noise as a test for many-body localization

et al. 2019

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“…Linearity of the intrinsic I − V 's, whereby all deviations from linearity are associated with electron heating, Altshuler et al [33] numerically solved the heat-balance equation P ∝ T β el − T β and showed that T el can, at low enough T , either be near equilibrium, or at a significantly higher T than that of the host lattice resulting in a far from thermodynamic equilibrium, high I state. Several experimental results [34][35][36] support this approach. In what follows we will refer to the low I (V < V th ), near equilibrium, regime as the high R (HR) state, and to the high I (V > V th ), out-of-equilibrium, regime as the low R (LR) state.We begin by following the low-T evolution of the breakdown of duality symmetry in one of our amorphous Indium Oxide (a:InO) films, GTIT1 [37].…”

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confidence: 71%

Nonequilibrium restoration of duality symmetry in the vicinity of the superconductor-to-insulator transition

Tamir¹,

Doron²,

Levinson³

et al. 2017

Phys. Rev. B

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The magnetic field driven superconductor to insulator transition in thin films is theoretically understood in terms of the notion of vortex-charge duality symmetry. The manifestation of such symmetry is the exchange of roles of current and voltage between the superconductor and the insulator. While experimental evidence obtained from amorphous Indium Oxide films supported such duality symmetry it is shown to be broken, counterintuitively, at low temperatures where the insulating phase exhibits discontinuous current-voltage characteristics. Here, we demonstrate that it is possible to effectively restore duality symmetry by driving the system beyond the discontinuity into its high current, far from equilibrium, state.The superconductor to insulator transition [1, 2] (SIT) is an experimentally accessible quantum phase transition [3]. By varying an externally controlled parameter in the Hamiltonian, a disordered superconducting thin film can be driven between its superconducting and insulating ground states [4][5][6][7][8][9][10][11]. Two decades ago Fisher theoretically studied [12] a specific case in which an applied magnetic field (B) drives the SIT. At low B, the induced Abrikosov vortices are localized by the disorder and a superconducting state prevails. Upon increasing B, Fisher found that the proliferation of vortices can result in a Bose-Einstein condensation of the vortex state that, in turn, leads to insulating behavior where the Cooperpairs are now localized [13][14][15][16][17][18][19][20][21][22]. The exchange of roles between the Cooper-pairs and vortices across the transition is analyzed via a duality transformation applied to the Hamiltonian [23].Experimentally, vortex-charge duality will manifest itself via the exchange of roles of current (I) and voltage (V ) between the superconductor and the insulator [24][25][26]. Duality symmetry implies that, for a given resistance (R ≡ V /I) measured at a given B = B SC in the superconductor, there exists a dual B = B Ins in the insulator where the conductivity (G ≡ I/V ) obeys the condition G(B Ins ) = R(B SC ). In previous publications [27,28] we found that our data follow a phenomenological, powerlaw, form across the SIT:where P (T ) ∼ Counterintuitively, duality symmetry breaks down at low temperatures (T 's) [28]. This is most conveniently illustrated through the deviations from the power-law dependence, graphically shown in Figure 1. Interestingly, these deviations appear only in the insulating side of the SIT. In the superconducting side, the data continue to follow the power-law dependence down to our lowest T 's [30].Together with the appearance of deviations from duality symmetry, our insulator develops strongly non-linear I − V characteristics (I − V 's) [31]. At T 0.2 K, applying a bias V above a well-defined V = V th (which is a function of both B and T ), results in a discontinuous increase, of several orders of magnitude, in I. Upon reducing V , a discontinuous decrease in I is observed recovering previous I values (see, for example, the 0.05 ...

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“…Here its use was inspired by earlier studies of the B-driven insulating phase of a:InO 32 . There, the discontinuities in the I-V's were attributed to bi-stable T el assuming thatR elÀph dominates the electrons cooling rate at low T's 20,25,33 . In Fig.…”

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confidence: 99%

The critical current of disordered superconductors near 0 K

et al. 2020

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An increasing current through a superconductor can result in a discontinuous increase in the differential resistance at the critical current. This critical current is typically associated either with breaking of Cooper-pairs or with the onset of collective motion of vortices. Here we measure the current-voltage characteristics of superconducting films at low temperatures and high magnetic fields. Using heat-balance considerations we demonstrate that the current-voltage characteristics are well explained by electron overheating enhanced by the thermal decoupling of the electrons from the host phonons. By solving the heat-balance equation we are able to accurately predict the critical currents in a variety of experimental conditions. The heat-balance approach is universal and applies to diverse situations from critical currents to climate change. One disadvantage of the universality of this approach is its insensitivity to the details of the system, which limits our ability to draw conclusions regarding the initial departure from equilibrium.

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Direct determination of the temperature of overheated electrons in an insulator

Cited by 9 publications

References 18 publications

Excessive noise as a test for many-body localization

Excessive noise as a test for many-body localization

Nonequilibrium restoration of duality symmetry in the vicinity of the superconductor-to-insulator transition

The critical current of disordered superconductors near 0 K

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