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Etienne Hofstetter

Publications and source records attributed to Etienne Hofstetter.

4 recordsLinked to original sources
arXiv2001

Boundary Conditions, the Critical Conductance Distribution, and One-Parameter Scaling

We study the influence of boundary conditions transverse to the transport direction for disordered mesoscopic conductors both at the Anderson metal-insulator transition and in the metallic regime. We show that the boundary conditions strongly influence the conductance distribution exactly at the metal-insulator transition and we discuss implications for the standard picture of one-parameter scaling. We show in particular that the scaling function that describes the change of conductance with system size depends on the boundary conditions from the metallic regime up to the metal-insulator transition. An experiment is proposed that might test the correctness of the one-parameter scaling theory.

cond-mat.mes-hall↗
arXiv1999

One-parameter Superscaling at the Metal-Insulator Transition in Three Dimensions

Based on the spectral statistics obtained in numerical simulations on three dimensional disordered systems within the tight--binding approximation, a new superuniversal scaling relation is presented that allows us to collapse data for the orthogonal, unitary and symplectic symmetry ($β=1,2,4$) onto a single scaling curve. This relation provides a strong evidence for one-parameter scaling existing in these systems which exhibit a second order phase transition. As a result a possible one-parameter family of spacing distribution functions, $P_g(s)$, is given for each symmetry class $β$, where $g$ is the dimensionless conductance.

cond-mat.dis-nn↗
arXiv1994

Shape Analysis of the Level Spacing Distribution around the Metal Insulator Transition in the Three Dimensional Anderson Model

We present a new method for the numerical treatment of second order phase transitions using the level spacing distribution function $P(s)$. We show that the quantities introduced originally for the shape analysis of eigenvectors can be properly applied for the description of the eigenvalues as well. The position of the metal--insulator transition (MIT) of the three dimensional Anderson model and the critical exponent are evaluated. The shape analysis of $P(s)$ obtained numerically shows that near the MIT $P(s)$ is clearly different from both the Brody distribution and from Izrailev's formula, and the best description is of the form $P(s)=c_1\,s\exp(-c_2\,s^{1+β})$, with $β\approx 0.2$. This is in good agreement with recent analytical results.

cond-mat↗