Onset of high-temperature superconductivity in the two-dimensional limit

Wang, T.; Beauchamp, K. M.; Berkley, D. D.; Johnson, B. C.; Liu, J. X.; Zhang, J.; Goldman, A. M.

doi:10.1103/physrevb.43.8623

Cited by 67 publications

(23 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…When plotted together on the same graph the apparent separatrix between the curves of the superconducting and insulating films was very close to the quantum resistance for pairs, h/Ae 2 or 6455 n [7,8]. Similar results have been found for ultrathin films of DyBa 2 Cu 3 0 7 -x [9].…”

supporting

confidence: 77%

Scaling of the insulator-to-superconductor transition in ultrathin amorphous Bi films

et al. 1991

View full text Add to dashboard Cite

Study of the electrical conductances of a series of ultrathin Bi films as a function of increasing thickness has revealed behavior which can be correlated with the onset of superconductivity, even in the insulating state. The conductances of these films scale empirically with a single parameter which falls to zero when the films become superconductive. These observations suggest a direct transition between insulating and superconducting behavior. This transition occurs at a normal-state sheet resistance close to the quantum resistance for pairs, R q =h/4e 2 .

show abstract

supporting

confidence: 77%

Scaling of the insulator-to-superconductor transition in ultrathin amorphous Bi films

et al. 1991

View full text Add to dashboard Cite

show abstract

“…In contrast, the higher-doped cuprates show quite distinct Tc versus p curves, which are strongly dependent on the doped-hole concentration. Closely related behavior has been found in YBa2Cu3O7_δ as the film was thinned down by ion bombardment [21] and in ultrathin DyBa2Cu3O7_δ films [22]. Superconductivity was found to disappear roughly at the 8heet resistance 6.5 kΩ.…”

Section: Universal Critical Quantum Properties Of Cuprate Superconducsupporting

confidence: 59%

“…6, which shows Tc versus σ(T = 0) a λ-2 (T = 0) for La2_ x SrCuO4_δ , HgBa2Cu04 + δ, and Tl2Ba2CuO6+δ [27,28], where the overdoped regime is accessible, there is some evidence of the nonuniversal behavior predicted by Eq. (22). Indeed, by approaching the critical end point 1, the data of La2_ x SrCuO4_δ and HgBa2Cu04+δ merge on the line describing the limiting universal behavior close to the d = 2 insulator-to-superconductor transition, whereas the data for overdoped materials indicates that the approach to end point 2 is nonuniversal.…”

Section: Universal Critical Quantum Properties Of Cuprate Superconducmentioning

confidence: 90%

Universal Critical Quantum Properties of Cuprate Superconductors

Schneider

1997

Acta Phys. Pol. A

View full text Add to dashboard Cite

Using the scaling theory of quantum critical phenomena we explore the occurrence of universal critical behavior at the insulator-to-superconductor and superconductor-to-normal state transitions at zero temperature. Experimentally, these phase transitions are driven by doping and correspond to critical end points of the phase transition łine in the temperature-hole concentration plane. Provided that the order parameter is a complex scalar in two dimensions, and that the London relation between superfluid number density and magnetic penetration depth holds, the scaling theory predicts universal behavior close to the insulator-to-superconductor transition. In particular, transition temperature and zero temperature penetration depth are universally related and the sheet resistance adopts a universal value. These predictions agree remarkably well with available experimental data and provide useful constraints for a microscopic theory.PACS numbers: 74.62.Dh Many physical properties of cuprate superconductors depend on hole doping. The generic doping dependence of the transition temperature Tc is depicted in Fig. 1. At a certain doping level, the so-called underdoped limit, these materials undergo at the hole concentration x" and T > O a transition from insulator to anomalous metal, and at T = O a transition from insulator to superconductor. As x is increased, Tc rises and reaches its maximum at x m . This behavior is shared by many cuprates, . In some compounds a further increase in the doping level leads to more metallic normal-state properties [8,9], but T, decreases and vanishes in the overdoped limit xo. Here, these materials undergo at T = O a superconductor-to-normal-state transition. A prominent example is La2_x S rx C uO4 _ δ [2].Another essential and doping-dependent property is the effective mass an-

show abstract

“…This value is universal and, apparently, equal to (2e) 2 /h (with 2e being the Cooper pair charge). There is strong experimental evidence 215,[278][279][280][281]19 that a variety of systems (metallic films, high-T c films, etc.) show the onset of superconductivity to occur when their sheet resistance falls below a value close to h/4e 2 ≈ 6.45kΩ.…”

Section: Discussionmentioning

confidence: 99%

Superconductivity and localization

1997

View full text Add to dashboard Cite

We present a review of theoretical and experimental works on the problem of mutual interplay of Anderson localization and superconductivity in strongly disordered systems. Superconductivity exists close to the metalinsulator transition in some disordered systems such as amorphous metals, superconducting compounds disordered by fast neutron irradiation etc. Hightemperature superconductors are especially interesting from this point of view. Only bulk systems are considered in this review. The superconductor-insulator transition in purely two-dimensional disordered systems is not discussed.We start with brief discussion of modern aspects of localization theory including the basic concept of scaling, self-consistent theory and interaction effects. After that we analyze disorder effects on Cooper pairing and superconducting transition temperature as well as Ginzburg-Landau equations for superconductors which are close to the Anderson transition. A necessary generalization of usual theory of "dirty" superconductors is formulated which allows to analyze anomalies of the main superconducting properties close to disorder-induced metal-insulator transition. Under very rigid conditions superconductivity may persist even in the localized phase (Anderson insulator).Strong disordering leads to considerable reduction of superconducting transition temperature T c and to important anomalies in the behavior of the upper critical field H c2 . Fluctuation effects are also discussed. In the vicinity of Anderson transition inhomogeneous superconductivity appears due to statistical fluctuations of the local density of states.We briefly discuss a number of experiments demonstrating superconductivity close to the Anderson transition both in traditional and high-T c superconductors. In traditional systems superconductivity is in most cases destroyed before metal-insulator transition. In case of high-T c superconductors a number of anomalies show that superconductivity is apparently conserved in the localized phase before it is suppressed by strong enough disorder. The concept of electron localization 1 is basic for the understanding of electron properties of disordered systems 2,3 . In recent years a number of review papers had appeared, extensively discussing this problem [4][5][6][7] . According to this concept introduction of sufficiently strong disorder into a metallic system leads to spatial localization of electronic states near the Fermi level and thus to a transition to dielectric state (Anderson transition). After this transition dc conductivity (at zero temperature, T = 0) vanishes, despite the finite value of electronic density of states at the Fermi level (at least in one-electron approximation).At the same time it is well-known that even the smallest attraction of electrons close to the Fermi level leads to formation of Cooper pairs and the system becomes superconducting at sufficiently low temperatures 8,9 . It is known that the introduction of disorder which does not break the time-reversal invariance (normal, nonm...

show abstract

Onset of high-temperature superconductivity in the two-dimensional limit

Cited by 67 publications

References 16 publications

Scaling of the insulator-to-superconductor transition in ultrathin amorphous Bi films

Scaling of the insulator-to-superconductor transition in ultrathin amorphous Bi films

Universal Critical Quantum Properties of Cuprate Superconductors

Superconductivity and localization

Contact Info

Product

Resources

About