Little-Parks Oscillations in an Insulator

Kopnov, G.; Cohen, Ori; Ovadia, M.; Lee, K. Hong; Wong, Chee Cheong; Shahar, D.

doi:10.1103/physrevlett.109.167002

Cited by 43 publications

(44 citation statements)

References 28 publications

(40 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the present case for f = 1/2, however, the transition is continuous but in a different universality class. The behavior of the magnetoresistance oscillations observed experimentally in superconducting films with a triangular lattice of nanoholes 18,19,21 are qualitatively consistent with the predictions from the model. We argued that the absence of secondary minima at f = 1/3 predicted by the model and the approximately linear behavior of the activation energy with film thickness are due to effects of Josephson-coupling disorder.…”

Section: Discussionsupporting

confidence: 79%

Superconductor-insulator transition of Josephson-junction arrays on a honeycomb lattice in a magnetic field

Granato

2016

Eur. Phys. J. B

View full text Add to dashboard Cite

We study the superconductor to insulator transition at zero temperature in a Josephson-junction array model on a honeycomb lattice with f flux quantum per plaquette. The path integral representation of the model corresponds to a (2+1)-dimensional classical model, which is used to investigate the critical behavior by extensive Monte Carlo simulations on large system sizes. In contrast to the model on a square lattice, the transition is found to be first order for f = 1/3 and continuous for f = 1/2 but in a different universality class. The correlation-length critical exponent is estimated from finite-size scaling of vortex correlations. The estimated universal conductivity at the transition is approximately four times its value for f = 0. The results are compared with experimental observations on ultrathin superconducting films with a triangular lattice of nanoholes in a transverse magnetic field.

show abstract

Section: Discussionsupporting

confidence: 79%

Superconductor-insulator transition of Josephson-junction arrays on a honeycomb lattice in a magnetic field

Granato

2016

Eur. Phys. J. B

View full text Add to dashboard Cite

show abstract

“…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.…”

mentioning

confidence: 99%

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

“…Monte Carlo simulation in the path-integral representation is used to determine the critical behavior and the universal resistivity at the transition as a function of disorder and average number of flux quanta per cell, fo. The resistivity increases with disorder for noninteger fo while it decreases for integer fo, and reaches a common constant value in a vortex-glass regime above a critical value of the flux disorder D There is growing interest in the superconductorinsulator (SI) transition in ultra-thin films with a lattice of nanoholes [1][2][3][4][5][6] . This system is an important testing ground for models of the universality class of the quantum phase transition since the patterned nanostructure provides a sensitive probe for distinguishing between phase and amplitude fluctuations of the superconducting order parameter.…”

mentioning

confidence: 99%

Magnetic flux disorder and superconductor-insulator transition in nanohole thin films

Granato

2016

Phys. Rev. B

View full text Add to dashboard Cite

We study the superconductor-insulator transition in nanohole ultrathin films in a transverse magnetic field by numerical simulation of a Josephson-junction array model. Geometrical disorder due to the random location of nanoholes in the film corresponds to random flux in the array model. Monte Carlo simulation in the path-integral representation is used to determine the critical behavior and the universal resistivity at the transition as a function of disorder and average number of flux quanta per cell, fo. The resistivity increases with disorder for noninteger fo while it decreases for integer fo, and reaches a common constant value in a vortex-glass regime above a critical value of the flux disorder D There is growing interest in the superconductorinsulator (SI) transition in ultra-thin films with a lattice of nanoholes [1][2][3][4][5][6] . This system is an important testing ground for models of the universality class of the quantum phase transition since the patterned nanostructure provides a sensitive probe for distinguishing between phase and amplitude fluctuations of the superconducting order parameter. The magnetoresistance oscillatory behavior at low magnetic fields near the transition is analogous to the one observed in microfabricated Josephsonjunction arrays, which undergo a SI transition due to the small electrical capacitance of the superconducting grains 7-11 . This common feature results from phase coherence effects, which can be described by the same generic model of phase fluctuations of the superconducting order parameter, a Josephson-junction array model, with a wider applicability. In fact, it is closely related to the Bose-Hubbard model, where Cooper pairs interact on a lattice potential, in the limit of a large number of bosons per site 8,12 , to the quantum rotor model [12][13][14] and to ultracold atoms on optical lattices 15-17 . For a periodic nanohole film at low magnetic fields, the simplest model consists of a frustrated array of superconducting "grains", where the phase is well defined locally, coupled by Josephson junctions or weak links on a periodic lattice, with the lattice of nanoholes corresponding to the dual lattice, which acts as a vortex pinning center 18,19 . The number of flux quanta per unit cell of the nanohole lattice, which is proportional to the external magnetic field, corresponds to the frustration parameter f of the Josephson-junction array model. The zero-temperature quantum phase transition in the array model, driven by the competition between the charging energy and Josephson-coupling energy at different frustration parameters, corresponds to the SI transition in the nanohole film in the external magnetic field. The resistivity at the transition is expected to be finite and universal 12,13,20,21 , depending only on the universality class of the transition, which generally changes in the presence of a magnetic field and disorder.Very recently, intriguing experimental results have been obtained near the SI transition in thin films with a disordered triangular l...

show abstract

Little-Parks Oscillations in an Insulator

Cited by 43 publications

References 28 publications

Superconductor-insulator transition of Josephson-junction arrays on a honeycomb lattice in a magnetic field

Superconductor-insulator transition of Josephson-junction arrays on a honeycomb lattice in a magnetic field

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

Magnetic flux disorder and superconductor-insulator transition in nanohole thin films

Contact Info

Product

Resources

About