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Prog. Theor. Phys. Vol. 111 No. 5 (2004) pp. 707-719

[ Full Text PDF : FREE ACCESS (241K) ]

Theory of the Superconductivity of MgB2

Toshio Soda1 and Yoshiyuki Fukumoto2

14-8-5, Sugano, Ichikawa 272-0824, Japan
2Department of Physics, Faculty of Science and Technology,
Tokyo University of Science, Noda 278-8510, Japan

(Received December 8, 2003)

Abstract:

We consider MgB2 to be a structure-dependent superconductor, the B2 plane of the MgB2 crystal to be superconducting and the Mg plane to be a tunneling junction plane between the B2 planes. We set up the superconducting interaction within the B2 plane between two adjacent planes and the coupling pair interactions in the perpendicular direction of the B2 plane. Using the mean field approximation for the equation of motion of the superconducting electron, we solve the Green function of the electron and obtain the order parameters Δ∥(T) and Δ⊥(T) of the intra B2 plane and inter B2 plane electrons, respectively. It is found that these two order parameters have the same T c with an appropriate choice of model parameters. Our gap function in the form Δ∥ + const ×Δ⊥ cos q, where q represents the momentum along the c-axis direction, leads to a two-peak structure in the density of states, which explains the experimental measurement of “two gaps" in MgB2. The bulk properties of the specific heat, the NMR and the thermal conductivity are also calculated.


URL : http://ptp.ipap.jp/link?PTP/111/707/
DOI : 10.1143/PTP.111.707

[ Full Text PDF : FREE ACCESS (241K) ] Citation:

References:

  1. J. Nagamatsu, N. Nakagawa, T. Muranaka, Y. Zentani and J. Akimitsu, Nature 410 (2001), 63[CrossRef].
  2. P. B. Allen, “Phonons and Superconductive Transition Temperature" in Dynamical Properties of Solids, ed. G. K. Horton and A. A. Maradudin (North Holland Co., Amsterdam, 1980).
  3. I. I. Mazin and V. P. Antrop, Physica C 385 (2003), 49[CrossRef].
  4. H. T. Choi, M. L. Cohen and S. G. Louie, Physica C 385 (2003), 66[CrossRef].
  5. P. C. Canfield and G. W. Crabtree, Phys. Today 56 (2003), 34.
  6. S. Souma, Y. Machida, T. Sato, T. Takahashi, H. Matsui, S.-C. Wang, H. Ding, A. Kaminski, J. C. Campuzano, S. Sasaki and K. Kadowaki, Nature 423 (2003), 65[CrossRef].
  7. M. Iavarone, G. Karapetrov, A. E. Koshelev, W. K. Kwok, G. W. Crabtree, D. G. Hinks, W. N. Kang, Eun-Mi Choi, Hyun Jung Kim, Hyeong-Jin Kim and S. I. Lee, Phys. Rev. Lett. 89 (2002), 187002[APS].
  8. T. Soda and Y. Wada, Prog. Theor. Phys. 36 (1966), 1111[PTP].
  9. F. Bouquet, R. A. Fisher, N. E. Phillips, D. G. Hinks and J. D. Jorgensen, Phys. Rev. Lett. 87 (2001), 047001[APS].
  10. G. Rickayzen, “The Theory of Bardeen, Cooper, and Schrieffer" in Superconductivity, vol. 1, ed. R. D. Parks (M. Dekker Inc., New York, 1967), p. 110.
  11. L. P. Kadanoff and P. C. Martin, Phys. Rev. 124 (1961), 670[APS].

Citing Article(s) :

  1. Progress of Theoretical Physics Vol. 115 No. 2 (2006) pp. 259-267 :
    A Possible Mechanism of Quartet Condensation for Room Temperature Superconductivity
    Toshio Soda and Yoshiyuki Fukumoto

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