Two-dimensional Lattice (two-dimensional + lattice)

Distribution by Scientific Domains


Selected Abstracts


Field-induced effects in the S = 1 two-dimensional Heisenberg antiferromagnet

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2005
M. E. Gouvêa
Abstract We use the self-consistent harmonic approximation to study the spin S = 1 Heisenberg antiferromagnet on a two-dimensional lattice in a uniform applied magnetic field. The magnetic field destroys the ,,(3) symmetry and an XY -like behavior, with a Berezinskii,Kosterlitz,Thouless (BKT) transition, is expected. We obtain the field dependence of the transition temperature for fields varying in a wide range. There has been experimental evidence that, for low dimensional spin systems, a gap can be induced by the applied magnetic field. We also investigate the behavior of this field-induced gap. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Hall conductivity as a topological invariant

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2005
A. Kunold
Abstract The object of the present work is to study the quantum Hall effect through its symmetries and topological aspects. We consider the model of an electron moving in a two-dimensional lattice in the presence of applied in-plain electric field and perpendicular magnetic field. We refer to this as the two dimensional electric,magnetic Bloch problem (EMB). The Hall conductivity quantization beyond the linear response approximation is analyzed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Towards the structure of the C-terminal part of the S-layer protein SbsC

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 10 2009
Markus Kroutil
The S-layer protein SbsC from Geobacillus stearothermophilus ATCC 12980 is the most prevalent single protein produced by the bacterium and covers the complete bacterial surface in the form of a two-dimensional crystalline monolayer. In order to elucidate the structural features of the assembly domains, several N-terminally truncated fragments of SbsC have been crystallized. Crystals obtained from recombinant fragments showed anisotropic diffraction to a maximum of 3.5,Å resolution using synchrotron radiation. The best diffracting crystals were obtained from rSbsC(755,1099), an unintentional in situ proteolytic degradation product of rSbsC(447,1099). Crystals were obtained in two different space groups, P21 and P41212, and diffracted to 2.6 and 3,Å resolution, respectively. Native and heavy-atom derivative data have been collected. The structure of the C-terminal part will yield atomic resolution information for the domains that are crucial for the assembly of the two-dimensional lattice. [source]


Multipolar Ordering in Electro- and Magnetostatic Coupled Nanosystems

CHEMPHYSCHEM, Issue 9 2008
Elena Y. Vedmedenko Dr. habil.
Abstract Electric and magnetic multipole moments and polarizabilities are important quantities in studies of intermolecular forces, non-linear optical phenomena, electrostatic, magnetostatic or gravitational potentials and electron scattering. The experimental determination of multipole moments is difficult and therefore the theoretical prediction of these quantities is important. Depending on purposes of the investigation several different definitions of multipole moments and multipole,multipole interactions are used in the literature. Because of this variety of methods it is often difficult to use published results and, therefore, even more new definitions appear. The first goal of this review is to give an overview of mathematical definitions of multipole expansion and relations between different formulations. The second aim is to present a general theoretical description of multipolar ordering on periodic two-dimensional lattices. After a historical introduction in the first part of this manuscript the static multipole expansion in cartesian and spherical coordinates as well as existing coordinate transformations are reviewed. On the basis of the presented mathematical description multipole moments of several symmetric charge distributions are summarized. Next, the established numerical approach for the calculation of multipolar ground states, namely Monte Carlo simulations, are reviewed. Special emphasis is put on the review of ground states in multipolar systems consisting of moments of odd or even order. The last section is devoted to the magnetization reversal in dense packed nanomagnetic arrays, where the magnetic multipole,multipole interactions play an important role. Comparison between the theory and recent experimental results is given. [source]