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DY: Dynamik und Statistische Physik
DY 15: Kritische Ph
änomene und Phasenumwandlungen I
DY 15.3: Talk
Monday, March 11, 2002, 15:00–15:15, H3
Finite Size Scaling of the Level Compressibility at the Anderson Transition — •Macleans Ndawana1, Rudolf Römer1, and Michael Schreiber1,2 — 1Institut für Physik, Technische Universität, D-09107 Chemnitz — 2International University Bremen, School of Engineering, D-28725, Bremen
We compute the number level variance Σ2 and the level compressibility χ from high precision data [1] for the Anderson model of localization and show [2] that they can be used in order to estimate the critical properties at the metal-insulator transition by means of finite-size scaling. With N, W, and L denoting, respectively, system size, disorder strength, and the average number of levels in units of the mean level spacing, we find that both χ(N,W) and the integrated Σ2 obey finite-size scaling. The high precision data was obtained for an anisotropic three-dimensional Anderson model with disorder given by a box distribution of width W/2. We compute the critical exponent as ν ≈ 1.45 ± 0.12 and the critical disorder as Wc ≈ 8.59 ± 0.05 in agreement with previous transfer-matrix studies in the anisotropic model. Furthermore, we find χ≈ 0.28 ± 0.06 at the metal-insulator transition in very close agreement with previous results [3].
[1] F. Milde, R. A. Römer and M. Schreiber, Phys. Rev. B 61, 6028 (2000)
[2] M. L. Ndawana, R. A. Römer and M. Schreiber, arXiv:cond-mat/0111090
[3] I. K. Zharekeshev and B. Kramer, Jpn. J. Appl. Phys.,34, 8A (1995)