Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 32: Poster I: Group II - Oxides
HL 32.4: Poster
Dienstag, 23. März 2010, 18:30–20:30, Poster D1
Ab initio studies on the structural parameters of ZnMgO alloys — •Marcel Giar, Markus Heinemann, and Christian Heiliger — I. Physikalisches Institut, Justus Liebig University Giessen, 35392 Giessen, Germany
Experimental and theoretical investigations on the lattice parameters of Zn1−xMgxO alloys in wurtzite structure show a decreasing c-axis and an increasing a-axis with increasing Mg concentration [1,2]. The ab initio computations [2] are based on density functional theory (DFT) in the local density approximation (LDA). We perform first-principle DFT calculations using the LDA as well as the generalized gradient approximation (GGA) for the exchange correlation functional. We determine the equilibrium lattice parameters of wurtzite Zn1−xMgxO alloys for different compositions ranging from 0≤ x ≤ 31.25 %. For the lattice constants a and c we find the same qualitative behavior as reported in [1] and [2]. LDA results show the typical underestimate of the lattice parameters while the values obtained by GGA excess the experimental results. We further find a deviation from Vegard’s law. For the unit cell volume we see a constant behavior independent of the Mg concentration.
[1] A.Ohtomo and A. Tsukazaki, Semicond. Sci. Technol. 20, S1-S12 (2005)
[2] X. F. Fan, H. D. Sun, Z. X. Shen, Jer-Lai Kuo and Y. M. Lu, J. Phys. Cond. Mat. 20 235521 (2008)