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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

Abstract

We used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La1.65Sr0.45CuO4La1.65Sr0.45CuO4, LSCO) and a cuprate insulator (La2CuO4La2CuO4, LCO), 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)σ(ω), of these films, and compared them to κκ-(BEDT-TTF)2Cu[N(CN)2]Br2Cu[N(CN)2]Br single crystals. The magnetic field HH 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)M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For HH perpendicular to the conducting layers, we observed almost identical behavior in both films and κκ-Br single crystals: (i) the transition onset in the inductive response, L-1kLk-1(T) occurs at a temperature lower by 2 K than in Reσ(T)Reσ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T)D(T) is exponential due to pinning of vortex cores. These results can be describedmore » 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:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; Russian Academy of Sciences
OSTI Identifier:
1390958
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
International Journal of Modern Physics B
Additional Journal Information:
Journal Volume: 29; Journal Issue: 25n26; Journal ID: ISSN 0217-9792
Publisher:
World Scientific
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Superconducting heterostructures; organic single crystals

Citation Formats

Gasparov, V. A., He, Xi, Dubuis, G., Pavuna, D., Kushch, N. D., Yagubskii, E. B., Schlueter, J. A., and Bozovic, I. 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. United States: N. p., 2015. Web. doi:10.1142/S0217979215420126.
Gasparov, V. A., He, Xi, Dubuis, G., Pavuna, D., Kushch, N. D., Yagubskii, E. B., Schlueter, J. A., & Bozovic, I. 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. United States. doi:10.1142/S0217979215420126.
Gasparov, V. A., He, Xi, Dubuis, G., Pavuna, D., Kushch, N. D., Yagubskii, E. B., Schlueter, J. A., and Bozovic, I. Tue . "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". United States. doi:10.1142/S0217979215420126.
@article{osti_1390958,
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},
author = {Gasparov, V. A. and He, Xi and Dubuis, G. and Pavuna, D. and Kushch, N. D. and Yagubskii, E. B. and Schlueter, J. A. and Bozovic, I.},
abstractNote = {We used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La1.65Sr0.45CuO4La1.65Sr0.45CuO4, LSCO) and a cuprate insulator (La2CuO4La2CuO4, LCO), 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)σ(ω), of these films, and compared them to κκ-(BEDT-TTF)2Cu[N(CN)2]Br2Cu[N(CN)2]Br single crystals. The magnetic field HH 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)M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For HH perpendicular to the conducting layers, we observed almost identical behavior in both films and κκ-Br single crystals: (i) the transition onset in the inductive response, L-1kLk-1(T) occurs at a temperature lower by 2 K than in Reσ(T)Reσ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T)D(T) is exponential due to pinning of vortex cores. These results can 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.},
doi = {10.1142/S0217979215420126},
journal = {International Journal of Modern Physics B},
issn = {0217-9792},
number = 25n26,
volume = 29,
place = {United States},
year = {2015},
month = {10}
}