Publikationstyp:  Zeitschriftenartikel 
URI (zitierfähiger Link):  http://nbnresolving.de/urn:nbn:de:bsz:352opus89955 
Autor/innen:  Esser, J.; Nowak, Ulrich; Usadel, KlausDieter 
Erscheinungsjahr:  1997 
Erschienen in:  Physical Review B ; 55 (1997), 9.  S. 58665872 
DOI (zitierfähiger Link):  https://dx.doi.org/10.1103/PhysRevB.55.5866 
Zusammenfassung: 
Exact ground states are calculated with an integer optimization algorithm for two and threedimensional sitediluted Ising antiferromagnets in a field (DAFF) and random field Ising ferromagnets (RFIM), the latter with Gaussian and bimodaldistributed random fields. We investigate the structure and the size distribution of the domains of the ground state and compare it to earlier results from Monte Carlo (MC) simulations for finite temperature. Although DAFF and RFIM are thought to be in the same universality class we found differences between these systems as far as the distribution of domain sizes is concerned. In the limit of strong disorder for the DAFF in two and three dimensions the ground states consist of domains with a broad size distribution that can be described by a power law with exponential cutoff. For the RFIM this is only true in two dimensions while in three dimensions above the critical field where longrange order breaks down the system consists of two infinite interpenetrating domains of up and down spins the system is in a twodomain state. For DAFF and RFIM the structure of the domains of finite size is fractal and the fractal dimensions for the DAFF and the RFIM agree within our numerical accuracy supporting that DAFF and RFIM are in the same universality class. Also, the DAFF groundstate properties agree with earlier results from MC simulations in the whole whereas there are essential differences between our exact groundstate calculations and earlier MC simulations for the RFIM which suggested that there are differences between the fractality of domains in RFIM and DAFF. Additionally, we show that for the case of higher disorder there are strong deviations from ImryMatype arguments for RFIM and DAFF in two and three dimensions.

Fachgebiet (DDC):  530 Physik 
Link zur Lizenz:  DepositLizenz 
ESSER, J., Ulrich NOWAK, KlausDieter USADEL, 1997. Exact groundstate properties of disordered Ising systems. In: Physical Review B. 55(9), pp. 58665872
@article{Esser1997Exact5005, title={Exact groundstate properties of disordered Ising systems}, year={1997}, doi={10.1103/PhysRevB.55.5866}, number={9}, volume={55}, journal={Physical Review B}, pages={58665872}, author={Esser, J. and Nowak, Ulrich and Usadel, KlausDieter} }
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Esser_1997_ExactGround_state.pdf  83 