The thermal diffusivity and thermal conductivity have been determined for lead iodide PbI2, at room temperature, using the photoacoustic spectroscopy. The result shows a thermal diffusivity αs=(25.0±0.4)×10−3 cm2/s, a value very close to other semiconductors of current technological importance. The electrical conductivity is also measured and discussed.

A spin-dependent variational theory is used to analyze the Rashba spin-orbit splitting in two-dimensional electron gases formed in III-V semiconductor inversion layers. The spin split conduction subbands in CdTe/InSb, insulator/InAs, InP/InGaAs, InAlAs/InGaAs, and AlGaAs/GaAs heterojunctions are calculated. The theory, presented here in detail, is based on the 8 × 8 k · p Kane model and on the introduction of simple and convenient spin-dependent Fang-Howard trial functions, and leads to analytical expressions for the split subbands, as well as allows for a detailed knowledge of the Rashba spin-orbit coupling, including its explicit dependence on structure parameters and its decomposition into separate contributions. The Rashba coupling parameter and the population difference in the spin-split subbands, as experimentally determined from the beating pattern of the Shubnikov-de Haas (SdH) oscillations, are obtained as a function of the electron density (n s ). The separate contributions to the particularly large Rashba splitting in CdTe/InSb heterojunctions are also computed and discussed. It is shown, for example, that due to the spin-dependent boundary conditions, the direct Rashba spin-orbit coupling term in the effective Hamiltonian dominates the splitting only for n s > 10 10 cm −2 while it is the barrier penetration kinetic energy term that gives the largest contribution to the Rashba effect at lower densities.

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We calculate the ground-state energies of muonic molecules formed by deuterium-deuterium, tritium-tritium, and deuterium-tritium nuclei plus a negative muon confined in a two-dimensional (2D) region. We show that the equilibrium distance between nuclei is a factor of 4 smaller and the vibrational energies are about a factor of 5 higher than the corresponding three-dimensional (3D) muonic molecules, thus favoring fusion reactions. In fact, the estimated d + t fusion rate is found to be three orders of magnitude higher in 2D than in 3D.