Measurement of a Superconducting Energy Gap in a Homogeneously Amorphous Insulator

Sherman, D.; Kopnov, G.; Shahar, D.; Frydman, A.

doi:10.1103/physrevlett.108.177006

Cited by 67 publications

(78 citation statements)

References 38 publications

(44 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The superconducting transition temperature T c , however, does decrease with increasing disorder and vanishes at a critical disorder, signaling a superconductor-insulator transition (SIT). These theoretical predictions are supported by scanning-tunneling-spectroscopy experiments [11][12][13][14] and by magnetoresistance oscillations [6] in disordered thin films.…”

Section: Introductionsupporting

confidence: 57%

Dynamical Conductivity across the Disorder-Tuned Superconductor-Insulator Transition

et al. 2014

View full text Add to dashboard Cite

We calculate the dynamical conductivity σðωÞ and the bosonic (pair) spectral function PðωÞ from quantum Monte Carlo simulations across clean and disorder-driven superconductor-insulator transitions (SITs). We identify characteristic energy scales in the superconducting and insulating phases that vanish at the transition due to enhanced quantum fluctuations, despite the persistence of a robust fermionic gap across the SIT. Disorder leads to enhanced absorption in σðωÞ at low frequencies compared to the SIT in a clean system. Disorder also expands the quantum critical region, due to a change in the universality class, with an underlying T ¼ 0 critical point with a universal low-frequency conductivity σ Ã ≃ 0.5ð4e 2 =hÞ.

show abstract

Section: Introductionsupporting

confidence: 57%

Dynamical Conductivity across the Disorder-Tuned Superconductor-Insulator Transition

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Other tunneling measurements on insulating InO x films confirmed that the gap persists [17]. Earlier electron transport experiments on films near the SIT revealed a giant magnetoresistance (MR) peak larger than expected for any known single electron transport mechanism [18,[32][33][34].…”

mentioning

confidence: 87%

“…The most prominent theories that can account for these behaviors view the SIT as a Cooper pair or boson localization transition, rather than a Cooper pair breaking transition [9][10][11][12][13][14]. Recent experiments that probe films near the SIT in new ways have provided more details that support this "bosonic" picture of the SIT [15][16][17][18][19]. For example, scanning tunneling microscopy (STM) has revealed that spatial inhomogeneities develop in the order parameter on approaching the SIT suggesting that Cooper pairs localize into islands [19,20].…”

mentioning

confidence: 99%

Collapse of the Cooper pair phase coherence length at a superconductor-to-insulator transition

Hollen

Fernandes

et al. 2013

Phys. Rev. B

View full text Add to dashboard Cite

We present investigations of the superconductor to insulator transition (SIT) of uniform a-Bi films using a technique sensitive to Cooper pair phase coherence. The films are perforated with a nanohoneycomb array of holes to form a multiply connected geometry and subjected to a perpendicular magnetic field. Film magnetoresistances on the superconducting side of the SIT oscillate with a period dictated by the superconducting flux quantum and the areal hole density. The oscillations disappear close to the SIT critical point to leave a monotonically rising magnetoresistance that persists in the insulating phase. These observations indicate that the Cooper pair phase coherence length, which is infinite in the superconducting phase, collapses to a value less than the interhole spacing at this SIT. This behavior is inconsistent with the gradual reduction of the phase coherence length expected for a bosonic, phase fluctuation driven SIT. This result starkly contrasts with previous observations of oscillations persisting in the insulating phase of other films implying that there must be at least two distinct classes of disorder tuned SITs. 1 arXiv:1301.6155v2 [cond-mat.supr-con] 4 Feb 2013Superconductor to insulator quantum phase transitions (SIT) can be induced in a wide range of quasi two-dimensional superconducting systems, including elemental films, high T c superconductors, organic superconductors and superconductor graphene composites [1][2][3][4][5][6][7][8]. Remarkably, these transitions occur, nearly universally, at a critical normal state resistance, R Nc ≃ R Q = h (2e) 2 , and film resistances often show scaling behavior around this critical point. The most prominent theories that can account for these behaviors view the SIT as a Cooper pair or boson localization transition, rather than a Cooper pair breaking transition [9][10][11][12][13][14]. Recent experiments that probe films near the SIT in new ways have provided more details that support this "bosonic" picture of the SIT [15][16][17][18][19]. For example, scanning tunneling microscopy (STM) has revealed that spatial inhomogeneities develop in the order parameter on approaching the SIT suggesting that Cooper pairs localize into islands [19,20]. High frequency transport measurements indicate that a finite superfluid density persists in non-superconducting films [21]. Here, we describe experiments employing a technique that is uniquely sensitive to the length scale that diverges at a bosonic SIT: the phase coherence length ξ φ . This technique previously revealed that Cooper pairs maintain their phase coherence over 100's of nanometers through the SITs of two distinct film systems [15,22].For this work, we investigate a third film system [23][24][25] that is likely to provide the most stringent test of whether the bosonic SIT is generic to thin films. This phase sensitive technique requires patterning films with an array of nanometer-scale holes.The hole patterning creates a simply connected geometry that leads to Little-Parks-like (LP) oscillations...

show abstract

“…Nanowires are strongly disordered, sometimes even being on the edge of a superconductor-insulator transition. Spectral and transport properties of strongly disordered superconductors on the edge of a superconductor-insulator transition are currently a topic of great interest both from experimental and theoretical points of view [10][11][12] . The transition is driven by the increase in the number of incoherent pairs at the expense of the ones that participate in the condensate.…”

Section: Hotspot In a Current-carrying Superconducting Nanowirementioning

confidence: 99%

Quasiparticle recombination in hotspots in superconducting current-carrying nanowires

et al. 2015

View full text Add to dashboard Cite

We describe a kinetic model of recombination of non-equilibrium quasiparticles generated by single photon absorption in superconducting current-carrying nanowires. The model is developed to interpret two-photon detection experiments in which a single photon does not possess sufficient energy for breaking superconductivity at a fixed low bias current. We show that quasiparticle selfrecombination in relaxing hotspots dominates diffusion expansion effects and explains the observed strong bias current, wavelength and temperature dependencies of hotspot relaxation in tungsten silicide superconducting nanowire single-photon detectors.

show abstract

Measurement of a Superconducting Energy Gap in a Homogeneously Amorphous Insulator

Cited by 67 publications

References 38 publications

Dynamical Conductivity across the Disorder-Tuned Superconductor-Insulator Transition

Dynamical Conductivity across the Disorder-Tuned Superconductor-Insulator Transition

Collapse of the Cooper pair phase coherence length at a superconductor-to-insulator transition

Quasiparticle recombination in hotspots in superconducting current-carrying nanowires

Contact Info

Product

Resources

About