Helmut Eschrig

The fundamentals of density functional theory

Part I: NON-RELATIVISTIC THEORY - Many-Body Systems - Density Matrices and Density Operators - Thomas-Fermi Theory - Hohenberg-Kohn Theory - Legendre Transfomation - Density Functional Theory by Lieb - Approximative Variants Part II: RELATIVISTIC THEORY - A Brief Introduction to Quantum Electrodynamics - Current Density Functional Theory

Relativistic density functional approach to open shells

A full application of relativistic spin‐density functional theory in noncollinear treatment of the exchange and correlation field is given to open‐shell atoms and ions of the carbon group. It is shown that the influence of noncollinearity is small as compared with self‐interaction corrections. Unfortunately, the defect of the local spin‐density approximation not to yield a source‐free exchange and correlation field increases in noncollinear treatment. © 1999 John Wiley & Sons, Inc. J Comput Chem 20: 23–30, 1999

Electric-field control of surface magnetic anisotropy: a density functional approach

In a recent experiment, Weisheit et al (2007 Science 315 349) demonstrated that the coercivity of thin L10 FePt and FePd films can be modified by the external electric field in an electrochemical environment. Here, this observation is confirmed by density functional calculations for the intrinsic magnetic anisotropy. The origin of the effect is clarified by means of a general and simple method to simulate charged metal surfaces. It is predicted that the coercivity of thin CoPt films is much more susceptible to electric field than that of FePt films.

Calculated magneto-optical Kerr spectra of compounds (X = V, Cr, Mn, Fe and Co)

The magneto-optical spectra of the compounds (with X = V, Cr, Mn, Fe and Co) are calculated for their ferromagnetic phase in the crystal structure, using density-functional band-structure theory. Large polar Kerr effects are predicted for several of these compounds, with - for a reasonable spectral broadening of 0.4 eV - maximum Kerr rotations of for and , for and , respectively. The Kerr spectra of , and with (001) magnetization are found to be very similar in shape, as are also those of and . The origin of the large Kerr effect in the alloys is shown to be caused by the spin - orbit coupling strength of Pt. A magnetic moment of moderate size on the 3d atom suffices in these materials to already create an appreciable Kerr effect. The influence of the optical transition matrix elements, magnetic moments and spin - orbit coupling strength on each of the constituent atoms are furthermore analysed. The orientation dependence of the polar Kerr spectra of some of the compounds are investigated by calculating in addition the polar Kerr spectra of some compounds for the (111) magnetization axis. The Kerr spectra of the (111) magnetization are found to be practically identical to that of the (001) magnetization.

First‐principles study of the giant magneto‐optical Kerr effect in MnBi and related compounds

First‐principles band‐structure calculations of the magneto‐optical Kerr spectra of MnBi and related compounds are reported. We find that band‐structure theory, based on density‐functional theory in the local spin‐density approximation, explains the measured Kerr effect of MnBi very well. A giant Kerr rotation of about −1.75° at 1.8 eV photon energy is given by our ab initio calculations, in accordance with recent experiments. A second peak at 3.4 eV in the Kerr rotation spectrum, however, comes out smaller in our calculations than what was recently measured. It is discussed that this can be due to the Mn–Bi stoichiometry. The microscopic origin of the giant Kerr effect in MnBi is analyzed in detail. We find that the huge Kerr effect in MnBi is caused by the combination of a sizeable magnetic moment of 3.7 μB on manganese, the large spin‐orbit coupling of bismuth, and a strong hybridization between the manganese d bands and the bismuth p states. The magneto‐optically active states are mainly the p states ...

Electronic structure and weak electron-phonon coupling in TaB 2

We present electronic structure calculations together with resistivity, susceptibility, and specific heat measurements for

Heavy fermion behavior of U2T2X compounds

{\mathrm{TaB}}_{2}

Tight-binding models for the iron-based superconductors

to search for the recently contradictorily reported superconductivity and to study related normal-state properties. We ascribe the absence of superconductivity down to 1.5 K for our

Superconducting rare earth transition metal borocarbides

{\mathrm{TaB}}_{2}

The High Field Project at Dresden/Rossendorf: A Pulsed 100 T/10 ms Laboratory at an Infrared Free-Electron-Laser Facility

samples to the generally weak electron-phonon coupling derived from comparison of the calculated and measured specific heat constants. For the