A scheme that reduces the calculations of ground-state properties of systems of interacting particles exactly to the solution of single-particle Hartree-type equations has obvious advantages. It is not surprising, then, that the density functional formalism, which provides a way of doing this, has received much attention in the past two decades. The quality of the energy surfaces calculated using a simple local-density approximation for exchange and correlation exceeds by far the original expectations. In this work, the authors survey the formalism and some of its applications (in particular to atoms and small molecules) and discuss the reasons for the successes and failures of the local-density approximation and some of its modifications.

The density functional formalism, its applications and prospects

Preface Acknowledgements Notation Part I. Overview and Background Topics: 1. Introduction 2. Overview 3. Theoretical background 4. Periodic solids and electron bands 5. Uniform electron gas and simple metals Part II. Density Functional Theory: 6. Density functional theory: foundations 7. The Kohn-Sham ansatz 8. Functionals for exchange and correlation 9. Solving the Kohn-Sham equations Part III. Important Preliminaries on Atoms: 10. Electronic structure of atoms 11. Pseudopotentials Part IV. Determination of Electronic Structure, The Three Basic Methods: 12. Plane waves and grids: basics 13. Plane waves and grids: full calculations 14. Localized orbitals: tight binding 15. Localized orbitals: full calculations 16. Augmented functions: APW, KKR, MTO 17. Augmented functions: linear methods Part V. Predicting Properties of Matter from Electronic Structure - Recent Developments: 18. Quantum molecular dynamics (QMD) 19. Response functions: photons, magnons ... 20. Excitation spectra and optical properties 21. Wannier functions 22. Polarization, localization and Berry's phases 23. Locality and linear scaling O (N) methods 24. Where to find more Appendixes References Index.

Electronic Structure: Basic Theory and Practical Methods

Full-potential, linearized augmented plane wave programs for crystalline systems

This review provides numerical and graphical information about many (but by no means all) of the physical and electronic properties of GaAs that are useful to those engaged in experimental research and development on this material. The emphasis is on properties of GaAs itself, and the host of effects associated with the presence of specific impurities and defects is excluded from coverage. The geometry of the sphalerite lattice and of the first Brillouin zone of reciprocal space are used to pave the way for material concerning elastic moduli, speeds of sound, and phonon dispersion curves. A section on thermal properties includes material on the phase diagram and liquidus curve, thermal expansion coefficient as a function of temperature, specific heat and equivalent Debye temperature behavior, and thermal conduction. The discussion of optical properties focusses on dispersion of the dielectric constant from low frequencies [κ0(300)=12.85] through the reststrahlen range to the intrinsic edge, and on the ass...

Semiconducting and other major properties of gallium arsenide

Annual review of condensed matter physics

Using the total-energy general-potential linearized-augmented-plane-wave method, we have tested the adequacy of the local-spin-density approximation for describing the magnetic and structural properties of iron. We find that there are fundamental deficiencies in the local-spin-density approximation, both quantitative and qualitative, in that there are substantial errors in the calculated ground-state volumes and magnetic moments, as well as a prediction of the wrong ground-state crystal structure.

/pdf/theory-of-magnetic-and-structural-ordering-in-iron-4qrkkx10c9.pdf

Theory of magnetic and structural ordering in iron.

The self-consistent electronic structures of Si, Ge, and zinc-blende GaP, GaAs, ZnS, and ZnSe have been determined using the linear combination of Gaussian orbitals method with a local-density form of the exchange-correlation functional. A completely general form of the spatial dependence of the potential has been used to describe accurately the bonding character in the tetrahedral environment. Results are presented for the valence- and conduction-band energies, densities of states, effective masses, and charge densities. Comparisons are made with previous calculations and with photoemission measurements. A striking result is that the local-density theory underestimates the optical band gaps by approximately 30% or more, although the general conduction-band topology is good. The theoretical valence-band energies, charge densities, and electron and hole effective masses are also in good agreement with experiment. The energies and wave functions presented here are used to determine the optical properties of these materials in the following paper.

First-principles electronic structure of Si, Ge, GaP, GaAs, ZnS, and ZnSe. I. Self-consistent energy bands, charge densities, and effective masses

While it is well known that three dimensional quantum many-body systems can support nontrivial braiding statistics between particlelike and looplike excitations, or between two looplike excitations, we argue that a more fundamental quantity is the statistical phase associated with braiding one loop α around another loop β, while both are linked to a third loop γ. We study this three-loop braiding in the context of (Z(N))(K) gauge theories which are obtained by gauging a gapped, short-range entangled lattice boson model with (Z(N))(K) symmetry. We find that different short-range entangled bosonic states with the same (Z(N))(K) symmetry (i.e., different symmetry-protected topological phases) can be distinguished by their three-loop braiding statistics.

Braiding statistics of loop excitations in three dimensions.

This Letter presents a general approach to calculation of the quasiparticle excitation energies of semiconductors which includes the energy dependence of the self-energy with a local density-functional approach. Both direct and indirect band gaps in Si are in much better agreement with experiment than are the bands from the ground-state theory. The relatively large corrections arise only after the dielectric screening of the electron gas is modified to account for a gap in the excitation spectrum.

Density-functional theory of excitation spectra of semiconductors; application to Si

The interband optical properties of Si, Ge, GaP, GaAs, ZnS, and ZnSe were calculated using ab initio self-consistent energy bands and wave functions obtained from the previous paper (paper I). Qualitatively good agreement with experiment is found, but all peak positions are shifted to lower energies since the local-density approximation underestimates the optical band gaps. Agreement with experiment with regard to line shape and peak position can be improved using an empirical energy-dependent self-energy correction as appears in the Sham-Kohn local-density theory of excitation. After examining the possible effects of lifetime broadening, our results indicate that additional many-body, excitonic, and local-field corrections must be included to achieve quantitative agreement in the intensity of certain features in the optical spectra.

Chenjie Wang

Papers

Theory of magnetic and structural ordering in iron.

First-principles electronic structure of Si, Ge, GaP, GaAs, ZnS, and ZnSe. I. Self-consistent energy bands, charge densities, and effective masses

Braiding statistics of loop excitations in three dimensions.

Density-functional theory of excitation spectra of semiconductors; application to Si

First-principles electronic structure of Si, Ge, GaP, GaAs, ZnS, and ZnSe. II. Optical properties