Covalent Bond Cluster Effects and Phase Transitions in Superconductor Mg_1-xAl_xB₂ Compounds

Abstract:

First-principle calculations were performed for the study of the superconductor MgB₂ and AlB₂. The doping effect of compound Mg_1-xAl_xB₂ was analyzed by supercell method. Band structure, electronic bands structure, total and partial densities of states were calculated and analyzed in detail. Covalent bond effects (CBC) appeared in the electronic bands structure when doping Al to MgB₂. It is found that this CBC effects on Mg_1-xAl_xB₂ samples have prominent relations to superconductivity. The study of the density of state indicates that the superconductivity decreases with the increase of compound Al. In particular, there exists the transition of superconductor to non-superconductor with the change of x. The theoretical predictions agreed well with experimental measurements.

• Periodical: Applied Mechanics and Materials (Volumes 55-57)
• Pages: 950-954
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.55-57.950
• Online since: May 2011
• Authors: Yan Bao, Yuan Zhao, Ni Zhu
• Keywords: APW Calculations, Electron Density of States, Transport Property

References

[1] J. Nagamatsu, N. Nakagawa, T. Muranaka et al., Nature (London) 410, 63 (2001).

[2] B. Adler, in Progress in Very High Pressure Research, edited by T. Bundy (Wiley, New York, 1960).

[3] N. Ashcroft, Phys. Rev. Lett. 21, 1748 (1968).

[4] M. Angst, S.L. Bud'ko, R.H.T. Wilke, and P.C. Canfield, Phys. Rev. B 71, 144512 (2005).

[5] J. Kortus, O.V. Dolgov, R.K. Kermer, and A.A. Golubov, Phys. Rev. Lett. 94, 027002 (2005).

[6] Y. Kong, O.V. Dolgov, O. Jepsen, and O.K. Andersen, Phys. Rev. B 64, 020501 (2001).

[7] K.P. Bohnen, R. Heid, and B. Renker, Phys. Rev. Lett. 86, 5771 (2001).

[8] J. Kortus, I.I. Mazin, K.D. Belashchenko et al. Phys. Rev. Lett. 86, 4656 (2001).

[9] K.D. Belashchenko, M. van Schilfgaarde, and V.P. Antropov, Phys. Rev. B 64, 092503 (2001).

[10] J.M. An and W. E Pickett, Phys. Rev. Lett. 86, 4366 (2001).

[11] W.L. McMillan, Phys. Rev. 167, 331 (1968).

[12] A.Y. Liu, I.I. Mazin, and J. Kortus, Phys. Rev. Lett. 87, 087005 (2001).

[13] R. Osborn, E.A. Goremychkin, A.I. Kolesnikov, and D.G. Hinks, Phys. Rev. Lett. 87, 017005 (2001).

[14] L. Romanò, A. Lascialfari, A. Rigamonti, and I. Zucca, Phys. Rev. Lett. 94, 247001 (2005).

[15] S. Galambosi, J.A. Soininen, A. Mattila et al. Phys. Rev. B 71, 060504 (2005).

[16] V.P. Zhukov, V.M. Silkin, E.V. Chulkov, and P.M. Echenique, Phys. Rev. B 64, 180507 (2001).

[17] W. Ku, W.E. Pickett, R.T. Scalettar, and A.G. Eguiluz, Phys. Rev. Lett. 88, 057001 (2002).

[18] J. Karpinski, N.D. Zhigadlo, G. Schuck et al. Phys. Rev. B 71, 174506 (2005).

[19] R.J. Cava, H. W. Zandbergen, and K. Inumaru, Physica C 385, 8 (2003).

[20] H.W. Zandbergen, M.Y. Wu, H. Jiang, M.A. Hayward, M.K. Haas, and R.J. Cava, Physica C. 366, 221 (2002).

[21] D.J. Singh, Plane waves Pseudopotentials and the LAPW Method (Kluwer Academic, Dordrecht, 1994).

[22] Anderson, Phys. Rev. B, 12, 3060 (1975).

[23] P. Blaha, K. Schwarz, G. Madsen, D. Kvasnicka, and J. Luitz, Computer code WIEN2K (Karlheinz Schwarz, Technische Universität Wien, Austria, 1999).

[24] R.W.G. Wyckoff, Crystal Structures (Wiley, New York, 1965), Vol. 1.