Modern Physics Letters B

We review the development of electronic structure methods for the calculation of nuclear magnetic resonance (NMR) properties in condensed matter over the last years. The key element is the extension of well-established approaches for the calculation of magnetic linear response to extended systems which are described under periodic boundary conditions. So far, two implementations have emerged which enable the calculation of NMR parameters within density functional theory in a pseudopotential plane wave scheme. We present the theoretical basis of the methods, further recent developments and a variety of selected applications. These applications are accompanied by comparisons with solid-state NMR experiments, exhibiting the strong impact of the symbiotic combination of high-level ab-initio calculations with experimental research.

This paper is concerned with thermostatistics of both D-dimensional Bose and Fermi ideal gases in a confining potential of type Arⁿ+Br^-n, where A, B are strictly positive constants and n is the power-law exponent. The investigation is performed in the framework of the semiclassical approximation. Some physical quantities for such systems are derived, like the density of states, density profiles and the number of particles. Bose–Einstein condensation (BEC) is discussed in the high and low temperature limits corresponding to T→∞ and T→0, respectively.

We compute the energy spectrum of the ground state of a 2D Dirac electron in the presence of a Coulomb potential and a constant magnetic field perpendicular to the plane where the the electron is confined. With the help of a mixed-basis variational method we compute the wave function and the energy level and show how it depends on the magnetic field strength. We compare the results with those obtained numerically as well as in the non-relativistic limit.

The polarization and susceptibility of thin antiferroelectric films are presented using a Green's function technique within an Ising model in a transverse field. Both quantities vary with the numbers of layers. Whereas at low temperatures the suceptibilty of the surface layer increases stronger than that of the second layer, the polarization of the surface is smaller compared to the polarization of the second layer. Such behavior has no counterpart in ferroelectric thin films. The effect is attributed to inhomogeneous thermal fluctuations.

We have derived rigorously the generating function for the number of pyramid-like polyhedra g(a,b,c) on the cubic lattice with width a, depth b, and height c.