A. K. McMahan

Cerium Volume Collapse: Results from the Merger of Dynamical Mean-Field Theory and Local Density Approximation

The merger of density-functional theory in the local density approximation (LDA) and many-body dynamical mean field theory (DMFT) allows for an ab initio calculation of Ce including the inherent 4f electronic correlations. We solve the DMFT equations by the quantum Monte Carlo (QMC) technique and calculate the Ce energy, spectrum, and double occupancy as a function of volume. At low temperatures, the correlation energy exhibits an anomalous region of negative curvature which drives the system towards a thermodynamic instability, i.e., the

Thermodynamic and spectral properties of compressed Ce calculated using a combined local-density approximation and dynamical mean-field theory

\gamma

Combined local-density and dynamical mean field theory calculations for the compressed lanthanides Ce, Pr, and Nd

-to-

Signatures of spin and charge energy scales in the local moment and specific heat of the half-filled two-dimensional Hubbard model

\alpha

Magnetic and Thermodynamic Properties of the Three-Dimensional Periodic Anderson Hamiltonian

volume collapse, consistent with experiment. The connection of the energetic with the spectral evolution shows that the physical origin of the energy anomaly and, thus, the volume collapse is the appearance of a quasiparticle resonance in the 4f-spectrum which is accompanied by a rapid growth in the double occupancy.

The screening of 4f moments and delocalization in the compressed light rare earths

We have calculated thermodynamic and spectral properties of Ce metal over a wide range of volume and temperature, including the effects of 4f electron correlations, by the merger of the local-density approximation and dynamical mean-field theory (DMFT). The DMFT equations are solved using the quantum Monte Carlo technique supplemented by the more approximate Hubbard-I and Hartree-Fock methods. At a large volume we find Hubbard split spectra, the associated local moment, and an entropy consistent with degeneracy in the moment direction. On compression through the volume range of the observed γ-α transition, an Abrikosov-Suhl resonance begins to grow rapidly in the 4f spectra at the Fermi level, a corresponding peak develops in the specific heat, and the entropy drops rapidly in the presence of a persistent, although somewhat reduced, local moment. Our parameter-free spectra agree well with experiment at the α- and γ-Ce volumes, and a region of negative curvature in the correlation energy leads to a shallowness in the low-temperature total energy over this volume range which is consistent with the γ-α transition. As measured by the double occupancy, we find a noticeable decrease in correlation on compression across the transition; however, even at the smallest volumes considered, Ce remains strongly correlated with residual Hubbard bands to either side of a dominant Fermi-level structure. These characteristics are discussed in light of current theories for the volume collapse transition in Ce.

Charge fluctuations and the valence transition in Yb under pressure.

This paper reports calculations for compressed Ce

Doping-dependent study of the periodic Anderson model in three dimensions

(4{f}^{1})

Local moment and specific heat in the Hubbard model

, Pr

Magnetic and Thermodynamic Properties of The 3-D Anderson Lattice Hamiltonian

(4{f}^{2})