Electronic Properties Of Liquid Alloys Research Articles

The electronic and structural properties of liquid Mg - Bi near the stoichiometric composition

The structure and electronic properties of liquid alloys with compositions close to the stoichiometric composition have been measured. The extremely deep minimum in the electronic conductivity observed previously at this composition is confirmed and shows a minimum value of which is characteristic of a good liquid semiconductor. In contrast, the thermopower of the samples never exceeds for all the compositions studied and is more typical of that expected for a poor liquid metal. Measurements of the liquid structure at the total structure factor level for and 0.42 reveal broadly similar diffraction patterns despite a change in conductivity of two orders of magnitude over this composition range. However, a small enhancement of the intensity of the pre-peak in the total structure factor at is observed at the stoichiometric composition and this may be indicative of stronger ordering in the Bi - Bi structure at stoichiometry. A detailed analysis of the total structure factors and a comparison with recent computer simulations confirm the ionic nature of the liquid. The electronic properties are discussed in terms of a charge-transfer-type density of electron states and it is concluded that the rapid change in conductivity and the low thermopowers are poorly understood using this framework. It is speculated that the unusual properties of this alloy are linked with an unusually high ionic mobility of Mg ions in the liquid.

Electronic properties of liquid metals and alloys calculated with the first-principles model (pseudo)potential of Bachelet, Hamann and Schluter: the Ga-Ge system

A model (pseudo)potential method has proven to be an interesting technique for calculating electronic properties in the framework of the Ziman formula for pure liquid metals and the Faber-Ziman expression for liquid alloys. First-principles model potentials are non-local and their parameters are energy dependent. In the alloy one must take into account an energy dependent effective mass, a depletion hole and the Fermi energy core shift which is not known for alloys. Furthermore, the thermopower explicitly includes an energy dependent contribution. The first-principles model (pseudo)potential of Bachelet, Hamann and Schluter (BHS) is energy independent and avoids the necessity of making these corrections (see Phys. Per. B, vol.26, p.4199, 1982). It has been used to calculate analytically the corresponding form factor. The resistivity and the thermopower of pure germanium and gallium and of the germanium-gallium alloy have been determined by using the Faber-Ziman formalism. Both hard sphere and experimental structure factors have been used (when available). The agreement between experimental and theoretical properties can be considered as good and confirms that the BHS model potential is adequate for describing the electronic properties of liquid alloys.

液体合金の構造と電子物性

液体合金の構造と電子物性

Higher-order correlation effects on thermodynamic and electronic properties of liquid alloys

The higher-order atom-atom correlation function effect, which has been recently revealed to be related to the origin of the minimum in the thermoelectric power Q of liquid Hg alloys, is discussed in some detail. New experimental results of the electrical resistivity ϱ and Q of liquid HgLi alloys are included in this discussion. The relation between the higher order correlation function effects and the thermodynamic function of liquid Hg alloys (the heat of mixing ΔH M) is stressed. The charge transfer effect, which can been clarified by the modified Miedema's plot, seems to produce the local structural change which can be seen as the higher order correlation effect.