84 citations · 550 across the 31 of their papers we have counts for
17 papers · 1 filter
Flux driven and geometry controlled spin filtering for arbitrary spins in aperiodic quantum networks
Amrita Mukherjee, Arunava Chakrabarti, Rudolf A. Roemer
We demonstrate that an aperiodic array of certain quantum networks comprising magnetic and non-magnetic atoms can act as perfect spin filters for particles with arbitrary spin stat…
Optimisation of multifractal analysis using box-size scaling
Alberto Rodriguez, Louella J. Vasquez, Rudolf A. Roemer
We study various box-size scaling techniques to obtain the multifractal properties, in terms of the singularity spectrum f(alpha), of the critical eigenstates at the metal-insulato…
Multifractal analysis of the metal-insulator transition in the 3D Anderson model I: Symmetry relation under typical averaging
Louella J. Vasquez, Alberto Rodriguez, Rudolf A. Roemer
The multifractality of the critical eigenstate at the metal to insulator transition (MIT) in the three-dimensional Anderson model of localization is characterized by its associated…
Multifractal analysis of the metal-insulator transition in the 3D Anderson model II: Symmetry relation under ensemble averaging
Alberto Rodriguez, Louella J. Vasquez, Rudolf A. Roemer
We study the multifractal analysis (MFA) of electronic wavefunctions at the localisation-delocalisation transition in the 3D Anderson model for very large system sizes up to $240^3…
Weak disorder expansion for localization lengths of quasi-1D systems
Rudolf A. Roemer, Hermann Schulz-Baldes
A perturbative formula for the lowest Lyapunov exponent of an Anderson model on a strip is presented. It is expressed in terms of an energy dependent doubly stochastic matrix, the…
Effects of Scale-Free Disorder on the Anderson Metal-Insulator Transition
Macleans L. Ndawana, Rudolf A. Roemer, Michael Schreiber
We investigate the three-dimensional Anderson model of localization via a modified transfer-matrix method in the presence of scale-free diagonal disorder characterized by a disorde…
The three-dimensional Anderson model of localization with binary random potential
I V Plyushchay, R A Roemer, M Schreiber
We study the three-dimensional two-band Anderson model of localization and compare our results to experimental results for amorphous metallic alloys (AMA). Using the transfer-matri…
Numerical investigations of scaling at the Anderson transition
Rudolf A Roemer, Michael Schreiber
At low temperature T, a significant difference between the behavior of crystals on the one hand and disordered solids on the other is seen: sufficiently strong disorder can give ri…
Thermoelectric Properties of Disordered Systems
R. A. Roemer, A. MacKinnon, C. Villagonzalo
The electronic properties of disordered systems have been the subject of intense study for several decades. Thermoelectric properties, such as thermopower and thermal conductivity,…
Metal-insulator transition in anisotropic systems
F. Milde, R. A. Roemer, M. Schreiber
We study the three-dimensional Anderson model of localization with anisotropic hopping, i.e., weakly coupled chains and weakly coupled planes. In our extensive numerical study we i…
Critical behavior of the thermoelectric transport properties in amorphous systems near the metal-insulator transition
C. Villagonzalo, R. A. Roemer, M. Schreiber +1
The scaling behavior of the thermoelectric transport properties in disordered systems is studied in the energy region near the metal-insulator transition. Using an energy-dependent…
Disorder and Two-Particle Interaction in Low-Dimensional Quantum Systems
Rudolf A. Roemer, Michael Schreiber, Thomas Vojta
We review some of the recent results on two-interacting particles (TIP) in low-dimensional disordered quantum models. Special attention is given to the mapping of the problem onto…
Exponents of the localization lengths in the bipartite Anderson model with off-diagonal disorder
Andrzej Eilmes, Rudolf A. Roemer, Michael Schreiber
We investigate the scaling properties of the two-dimensional (2D) Anderson model of localization with purely off-diagonal disorder (random hopping). In particular, we show that for…
Off-diagonal disorder in the Anderson model of localization
P. Biswas, P. Cain, R. A. Roemer +1
We examine the localization properties of the Anderson Hamiltonian with additional off-diagonal disorder using the transfer-matrix method and finite-size scaling. We compute the lo…
Phase diagram of the three-dimensional Anderson model of localization with random hopping
P. Cain, R. A. Roemer, M. Schreiber
We examine the localization properties of the three-dimensional (3D) Anderson Hamiltonian with off-diagonal disorder using the transfer-matrix method (TMM) and finite-size scaling…
Transport properties near the Anderson transition
C. Villagonzalo, R. A. Roemer, M. Schreiber
The electronic transport properties in the presence of a temperature gradient in disordered systems near the metal-insulator transition [MIT] are considered. The d.c. conductivity…
Energy Levels of Quasiperiodic Hamiltonians, Spectral Unfolding, and Random Matrix Theory
Michael Schreiber, Uwe Grimm, Rudolf A. Roemer +1
We consider a tight-binding Hamiltonian defined on the quasiperiodic Ammann-Beenker tiling. Although the density of states (DOS) is rather spiky, the integrated DOS is quite smooth…