Hamburg 2001 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 25: Postersitzung III: Pinning und Vortexdynamik, Massive HTSL, Bandleiter, Transporteigenschaften in HTSL, SL dünner Filme, Elektronen und Phononen in HTSL, Tunneln, Borkarbide, Quantenphasen und Metall-Isolator-Überg
änge, Anwendungen, Sonstiges
TT 25.64: Poster
Donnerstag, 29. März 2001, 14:30–17:00, Rang S\ 3
Finite Size Scaling of the Level Compressibility at the Anderson Transition — •Macleans Ndawana, Rudolf A. Römer, and Michael Schreiber — Institut für Physik, Technische Universität, D-09107 Chemnitz
We compute the number level variance Σ2 and the level compressibility χ from high precision data for the Anderson model of localization and show that they can be used in order to estimate the critical properties at the metal-insulator transition by scaling. With N, W, and L denoting 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 quantity η(N,W)=1/30∫030Σ2(W,N,L)dL obey finite-size scaling. The high precision data [1] was obtained for an anisotropic three-dimensional Anderson model with box disorder distribution of width W/2. We compute the localization length critical exponet as ν ≈ 1.43 ± 0.04 and the critical disorder as Wc ≈ 8.57 ± 0.04 in agreement with previous transfer-matrix studies in the anisotropic model [2]. Furthermore, we find χ≈ 0.5 at the metal-insulator transition in agreement with its theoretical estimate [3].
[1] F. Milde, et. al Phys. Rev. B 61, 6028(2000).
[2] F. Milde, et. al Eur. Phys. J. B 15, 685(2000).
[3] V. E. Kravtsov, et. al Phys. Rev. Lett. 79, 1913(1997).