NISCAIR Online Periodicals Repository

NISCAIR ONLINE PERIODICALS REPOSITORY (NOPR)  >
NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.48 [2010] >
IJPAP Vol.48(01) [January 2010] >


Title: Pseudopotential approach to superconductivity in MgB2
Authors: Sharma, K S
Bhargava, Nidhi
Jain, Ritu
Goyal, Varsha
Sharma, Ritu
Sharma, Smita
Keywords: Superconductivity
Pseudopotential
Transition temperature
Isotope effect
Electron-phonon interaction
Issue Date: Jan-2010
Publisher: CSIR
Abstract: Superconductivity in MgB2 has been re-examined in BCS-Eliashberg framework by employing Mc-Millan’s [Phys Rev, 167 (1968) 331] Tc-equation and form factors of MgB2 computed from the form factors of component metals (Model-I). The empty core model pseudopotential due to Ashcroft [Phys Lett, 23 (1966) 48] and random phase approximation form of dielectric screening due to Gellmann and Brueckner [Phys Rev, 106 (1958) 364] are used in the present work. An excellent agreement between the present values and other theoretically computed values of Tc and with the relevant experimental data for MgB2 confirms the validity of the present approach. The explicit dependence of λ and Tc on the isotopic masses of Mg and B, as revealed from the present work, confirms the role of lattice vibrations in the superconducting behaviour of MgB2 and the high value of Tc in it may be attributed to the phonon mediated e-e interaction coupled with higher values of phonon frequencies due to light mass of B atoms. It has also been observed that the pseudo-atom model (Model-II) with appropriate choice of the potential parameter rc successfully explains high value of Tc and isotope effect in MgB2, confirming the prominent role played by electron-phonon interaction in the high-Tc superconductivity observed in MgB2. The isotope effect exponent -values obtained from the two models are in complete agreement with each other and the present value = 0.46 is also much closer to the BCS value of 0.5. Interaction strength N0V values obtained from the two models are also in perfect agreement with each other and the present value N0V = 0.48 suggests that MgB2 is a strong coupling superconductor.
Page(s): 59-66
ISSN: 0975-1041 (Online); 0019-5596 (Print)
Source:IJPAP Vol.48(01) [January 2010]

Files in This Item:

File Description SizeFormat
IJPAP 48(1) 59-66.pdf507.08 kBAdobe PDFView/Open
 Current Page Visits: 588 
Recommend this item

 

National Knowledge Resources Consortium |  NISCAIR Website |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2012 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 511363 since 06-Feb-2009  Last updated on 11-Apr-2014Webmaster: nopr@niscair.res.in