Dynamical corrections to density-functional theory for quasiparticles in ferromagnetic 4f systems. II. Finite-temperature results for EuO

Journal Article · Fri May 01 04:00:00 EDT 1987 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.35.7025· OSTI ID:6046993

Nolting, W; Borgiel, W; Borstel, G

We present a theory for the temperature dependence of the electronic quasiparticle spectrum of ferromagnetic 4f systems. A concrete evaluation for the semiconductor EuO is performed and discussed. The study is based on a d-f exchange model, which has been exactly solved for T = 0 in part I of this series. The exact solution allows us to fix the ''free'' Bloch energies epsilon-c/sub m/(k) of the model in a highly realistic manner by application of a self-consistent spin-polarized band-structure calculation based on density-functional theory. For finite temperatures the d-f model is approximately solved by a many-body procedure, which takes special care for a proper treatment of spin-exchange processes between localized 4f moments and itinerant conduction electrons. The method reproduces the exact T = 0 limiting case. The resulting f-spin correlation functions are calculated by a moment method. We discuss in detail the one-electron spectral density for k vectors along the GAMMAL direction, real and imaginary parts of the electronic self-energy, and quasiparticle densities of states. The prominent peaks of the spectral density are used to construct a temperature-dependent quasiparticle band structure. The temperature dependence is to first order due to the magnetization, and to second order due to a transverse correlation function of the localized 4f spins.

• Research Organization: Institut fuer Theoretische Physik II, Westfalische Wilhelms Universitaet, D-4400 Muenster Domagkstrasse 75, Federal Republic of Germany
• OSTI ID: 6046993
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 35:13; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
BLOCH THEORY
CHALCOGENIDES
CORRELATION FUNCTIONS
EUROPIUM COMPOUNDS
EUROPIUM OXIDES
FERROMAGNETIC MATERIALS
FUNCTIONS
MAGNETIC MATERIALS
MANY-BODY PROBLEM
MATERIALS
MOMENTS METHOD
ORIENTATION
OXIDES
OXYGEN COMPOUNDS
QUASI PARTICLES
RARE EARTH COMPOUNDS
SPIN ORIENTATION
TEMPERATURE DEPENDENCE