arXiv subjects

G. A. Gehring

Publications and source records attributed to G. A. Gehring.

21 records · Page 2Linked to original sources

arXiv1993

Theory of an elastic anomaly in the heavy fermion system CeTe

The elastic anomaly observed in the coherent Kondo state of Ce heavy fermion compounds is analyzed by using the Anderson lattice model simulating the energy level scheme of CeTe. The $Γ_7$ doublets and $Γ_8$ quartets of the 4f states are considered in the model. We solve the mean field equations to derive the temperature dependences of elastic constants, using the random phase approximation like expression for the interaction between the elastic strain and the crystalline field splitting. We compare the calculation with the $(c_{11} - c_{12})/2$ and $c_{44}$ constants of CeTe. The presence of the downward dip and the observed overall temperature variations of the two constants are well described by the present theory. The origin of the dip is the coupling between the elastic strain and the splitting of the $Γ_8$ quartets.

cond-mat↗

arXiv1993

Elastic anomaly of heavy fermion systems in a crystalline field II

An elastic anomaly, observed in the heavy Fermi liquid state of Ce alloys (for example, CeCu_6 and CeTe), is analyzed by using the infinite-U Anderson lattice model. Four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting 2 Delta is assumed between two energy levels. Fourfold degenerate conduction bands are also considered. We solve the model using the mean field approximation to slave bosons and the renormalized elastic constant is calculated. The temperature dependence of the constant shows the downward dip. The result is compared with the experimental data of CeTe.

cond-mat↗

arXiv1993

Elastic anomaly of heavy fermion systems in a crystalline field

An elastic anomaly, observed in the heavy fermi liquid state of Ce alloys (for example, CeCu$_6$ and CeTe), is analyzed by using the infinite-$U$ Anderson lattice model. The four atomic energy levels are assumed for f-electrons. Two of them are mutually degenerate. A small crystalline splitting $2Δ$ is assumed between two energy levels. The fourfold degenerate conduction bands are also considered in the model. We solve the model using the mean field approximation to slave bosons, changing the Fermi energy in order to keep the total electron number constant. The nonzero value of the mean field of the slave bosons persists over the temperatures much higher than the Kondo temperature. This is the effect of the constant electron number. Next, the linear susceptibility with respect to $Δ$ is calculated in order to obtain the renomalized elastic constant. The resulting temperature dependence of the constant shows the downward dip. We point out the relation of our finding with the experimental data.

cond-mat↗