Eijiro Sakai

Ionic Conductivity and Thermoelectric Power of Superionic Conductors in the Lattice Gas Model

The ionic conductivity and the thermoelectric power in superionic conductors are expressed as functions of the concentration of ions and the interaction energy in the framework of the lattice gas model. Under appropriate conditions, the results obtained are in good agreement with those of experiments.

Thermal conductivity in superionic conductors

Abstract The contribution of mobile ions to the thermal conductivity in superionic conductors is investigated by making use of the lattice gas model with a hopping term. The thermal conductivity is obtained as a function of an ion concentration and a repulsive interaction energy between the nearest neighbors. It is shown that the contribution of mobile ions to the thermal conductivity is of an Arrhenius type in the usual temperature region in which measurements are conducted.

Thermal conduction by mobile ions in superionic conductors

The contribution of mobile ions to the thermal conductivity in superionic conductors is investigated by making use of the lattice gas model with a hopping term. The thermal conductivity is obtained as a function of ion concentration and repulsive interaction energy between the nearest neighbors. It is shown that the contribution of mobile ions to the thermal conductivity is of an Arrhenius type in the usual temperature region in which measurements are conducted.

Systematic Derivation of the Number-Phase Distribution Functions

We propose a unified method for obtaining the number-phase distribution functions in the extended Fock space and apply it to various distribution functions. A physical number-phase distribution function is easily obtained; it is the expectation value of an extended Wigner operator in a physical state. This method corresponds to Cohen’s method for the positionmomentum Wigner functions. The properties of the number-phase distribution functions and their relations are presented in a unified manner. Also, through the distribution functions, the correspondence between classical functions and quantum operators is obtained explicitly.

The Number-Phase Wigner Function in the Extended Fock Space

On the basis of the phase states, we present the correct integral expressions of the two number-phase Wigner functions discovered so far. These correct forms are derived from those defined in the extended Fock space with negative number states. The analogous conditions to Wigners original ones cannot lead to the number-phase function uniquely. To show this fact explicitly, we propose another function satisfying all these conditions. It is also shown that the ununiqueness of the number-phase Wigner function result from the phase-periodicity problem.

F ermi Surfaces of Eu Compounds

A high quality single crystal of EuBi3 was grown and a de Haas-van Alphen (dHvA) measurement has been done with the compound. In order to explain the experimental result of the angular dependence of the dHvA frequency in EuBi3, a relativistic linear augmented-plane-wave method with the exchange-correlation potential in the local density approximation has been performed to non-4f reference compound SrBi3. The topology of the Fermi surface of EuBi3 is explained well by our band calculation.

The Number-Phase and Position-Momentum Distribution Functions

We present the relationship between the number-phase and position-momentum quantum distribution functions using the extended Liouville space. We also propose an extended Ban’s number-phase distribution function in the extended space, and show that the other distribution functions can be expressed in terms of Ban’s function. Moreover, two new number-phase distribution functions, the Born-Jordan and the Cohen distribution functions, are given in a unified manner. Subject Index: 060

Effect of 5d—eg population in CeAg1−xInx

Abstract The saturation magnetization of polycrystalline CeAg 1− x In x measured in magnetic fields up to 15 T at 1.5 K is about 1.5 μ B and 1.0 μ B for x ⩽0.2 and x ⩾0.3, respectively. Reversal of the crystalline electric field (CEF) occurs from Γ 8 ground state to Γ 7 . The susceptibility can be approximated by the cubic CEF in the tetragonal phase, however, it cannot be represented in the cubic phase for x >0. The atomic shifts in the tetragonal phase widen the volume available for Ce, corresponding to reduction of about 13 kbar pressure. The results are discussed with the 5d—e g conduction band population.

Field induced superconductivity of CeRu2

Abstract Temperature dependence of the magnetic susceptibility was measured for CeRu2 in fields up to 2T. Tc=6.55K in zero field. It was found the Tc splits into 3 peaks for H>0.8T. The transition of the highest Tc (TcH) is very sharp. Temperature hysteresis was not observed on TcH, but observed on the other two.