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Title: Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La1.65Sr0.45CuO4/La2CuO4 films and the organic superconductors κ-(BEDT-TTF)2Cu[N(CN)2]Br

In this study, we used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La1.65Sr0.45CuO4) and a cuprate insulator (La2CuO4), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κκ-(BEDT-TTF)2Cu[N(CN)2]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz using either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, Lk–1(T) occurs at a temperature lower by 2 K than in Re σ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results canmore » be described by the extended dynamic theory of the Berezinski–Kosterlitz–Thouless (BKT) transition and dynamics of bound vortex–antivortex pairs with short separation lengths.« less
Authors:
;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [5]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)
  3. Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland)
  4. Institute of Problems of Chemical Physics RAS, Chernogolovka (Russia)
  5. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1235867
Report Number(s):
BNL--111659-2015-JA
Journal ID: ISSN 0217-9792; R&D Project: MA509MACA; KC0203020
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
International Journal of Modern Physics B
Additional Journal Information:
Journal Volume: 29; Journal Issue: 25-26; Journal ID: ISSN 0217-9792
Publisher:
World Scientific
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY superconducting heterostructures; organic single crystals