Electronic States in Liquid and Amorphous Metals.
Abstract
This thesis deals with the calculation of the electronic spectrum of closepacked structurally disordered systems such as liquid and amorphous metals. Because of their potential in technology, metallic glasses are of considerable current interest both experimentally and theoretically. The key to understanding many of their physical properties is their electronic structure. We limit ourselves to the consideration of electron states in the oneelectron approximation and to systems in which at least one atomic species is a noble or transition metal. Here the delectrons undergo resonant scattering and the average spectrum cannot be described in terms of finite order perturbation theory. We apply the Effective Medium Approximation (EMA) to systems having a muffintin Hamiltonian. The systems that we study are molten Cu and NiP and NiB alloys. We calculate the densities of states and the resistivities of liquid Cu at two different temperatures. We also show that the randomnumber based annealing techniques of statistical physics can be used to obtain two site distribution functions that are suitable for use in our model. We calculate the complete electronic spectra of NiP and NiB alloys. We constructed selfconsistent muffintin potentials as input parameters for these calculations. Our firstprinciple calculations predict reasonable values for the negative temperature coefficient of the resistivity for liquid Cu (for the appropriate range of Fermi energies) and thus provide support for the Faber Ziman semiempirical model. Our results for the alloy calculations are discussed in the light of the NagelTauc model regarding electronic contributions to the reltive stability of metallic glasses. We conclude that the NagelTauc model is not appropriate for transition metalmetalloid alloys though their ideas may be relevant for noble metalmetalloid systems. In the future, as the required structural data becomes available for a wider range of alloy systems, EMA calculations will play an increasingly important role in understanding the electronic properties of metallic glasses.
 Publication:

Ph.D. Thesis
 Pub Date:
 1986
 Bibcode:
 1986PhDT........62M
 Keywords:

 Physics: Electricity and Magnetism; Engineering: Metallurgy