Rezakhani , A. T. and Afzali , R. (2006) *Order parameter of a nanometre-scale s-wave superconducting grain in quantum tunnelling process: Frequency space analysis.* CHINESE PHYSICS LETTERS , 23 (4). pp. 967-970. ISSN 0256-307X

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Official URL: http://iopscience.iop.org/0256-307X/23/4/057/?ejre...

## Abstract

A nano-scale s-wave superconducting grain, coupled to a normal metallic contact through a tunnelling junction, is placed in an external magnetic field. We suppose that effect of this quantum tunnelling on the Fourier transform of the order parameter is in the form of a small additive correction to the BCS order parameter. At the first order approximation in terms of this correction term and by using an instanton method, the related Green functions (in frequency space) are obtained. By establishing a self-consistent configuration an analytic formula for the order parameter is also found. We also show that a departure from superconductivity can be captured by this formula. This change of state is indeed a manifestation of a quantum transition induced by quantum fluctuations. In this sense, this is an advantage of our simple method which, like other more elaborate methods, can detect a quantum transition in the state of the grain.

Item Type: | Article |
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Subjects: | Physical Science > Nanophysics Physical Science > Nano objects Material Science > Nanochemistry Material Science > Nanostructured materials |

Divisions: | Faculty of Engineering, Science and Mathematics > School of Physics Faculty of Engineering, Science and Mathematics > School of Chemistry |

ID Code: | 7324 |

Deposited By: | JNCASR |

Deposited On: | 28 Oct 2009 09:40 |

Last Modified: | 28 Oct 2009 09:40 |

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