Abstract
The valence charge density distribution for the icosahedral AlPdMn (i-AlPdMn) quasicrystal was obtained with the structure factors of the nine strongest symmetry inequivalent reflections, which were refined by using the quantitative convergent beam electron diffraction (QCBED) technique. It shows that the bonding charge is localized. The enhanced charge density in the middle of the aluminum-transition-metal (Al-TM) bond shown in the valence charge density distribution is the characteristic of covalent bonding. Assuming that the shape of an atom is a sphere with covalent radius, the number of electrons that each atom gains or loses in 55 different pseudo-Mackay clusters (PMCs) was calculated based on the obtained valence charge density distribution. It indicates that almost all the atoms lose electrons except a few Pd atoms that are in some particular shells. It also shows that the atoms of an identified element could have different valences because of chemically and/or structurally different local environments in which the atoms situate. Regardless of the topology and chemical occupancy, the number of valence electrons per atom in a cluster is close to 1.69. This strongly suggests that the pseudo-Mackay clusters are stabilized at a certain electron concentration.
Similar content being viewed by others
References
Stadnik Z M. Physical Properties of Quasicrystals[M]. Berlin: Springer-Verlag, 1999.
Pauling L. The Nature of the Interatomic Force in Metals [J]. Phys Rev, 1938, 54: 899–904.
Tsai A P. A Test of Hume-Rothery Rules for Stable Quasicrystals[J]. J Non-Cryst Solids, 2004, 334–335: 317–332.
Zuo J M. Measurements of Electron Densities in Solids: A Real-Space View of Electronic Structure and Bonding in Inorganic Crystals[J]. Rep Prog Phys, 2004, 67: 2053–2103.
Boudard M, de Boissieu M, Janot C, et al. Neutron and X-Ray Single-Crystal Study of the AlPdMn Icosahedral Phase[J]. J Phys: Condens Matter, 1992, 4: 10149–10168.
Fang A, Zou H, Yu F, et al. Structure Refinement of the Icosahedral AlPdMn Quasicrystal Using Quantitative Convergent Beam Electron Diffraction and Symmetry-Adapted Parameters[J]. J Phys: Condens Matter, 2003, 15: 4947–4960.
Yu F, Zou H, Wang J, et al. Investigation of the Surface Terminations of Icosahedral AlPdMn Quasicrystal Based on a Modified Non-Spherical Model[J]. J Phys: Condens. Matter, 2004, 16: 6821–6834.
Yu F, Zou H, Wang J, et al. Charge Density Determination in Icosahedral AlPdMn Quasicrystal Using Quantitative Convergent Beam Electron Diffraction[J]. Micron, 2004, 35: 411–418.
Krajčí M, Hafner J. Semiconducting Al-Transition-Metal Quasicrystals[J]. Phys Rev B, 2003, 68: 165202.
Krajčí M, Hafner J. Covalent Bonding and Band-Gap Formation in Ternary Transition-Metal Di-Aluminides: Al4MnCo and Related Compounds[J]. J Phys: Condens Matter, 2002, 14: 7201–7219.
Krajčí M, Windisch M, Hafner J, et al. Atomic and Electronic Structure of Icosahedral Al-Pd-Mn Alloys and Approximant [J]. Phys Rev B, 1995, 51: 17355–17378.
Evans R C. An Introduction to Crystal Chemistry[M]. London: Cambridge University Press, 1976.
Author information
Authors and Affiliations
Corresponding author
Additional information
Foundation item: Supported by the National Natural Science Foundation of China (50671073)
Biography: YU Fengmei (1965–), female, Professor, Ph.D., research direction: quasicrystal physics.
Rights and permissions
About this article
Cite this article
Yu, F., Chen, Z., Wang, J. et al. Experimental measurement of valence electron concentration of icosahedral AlPdMn quasicrystal. Wuhan Univ. J. Nat. Sci. 14, 223–228 (2009). https://doi.org/10.1007/s11859-009-0307-5
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11859-009-0307-5