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The low temperature electronic specific heat as a function of Au content in Cu-Au alloys shows interesting features. The specific heat coefficient of disordered alloys lies on a smooth curve below the linearly interpolated elemental metal values. Ordering reduces the value of this coefficient in all cases except that of the CuAu I alloy. It is shown that this behaviour of the electronic specific heat is due to the specific structure of the electronic density of states around the Fermi level. The position and shape of the large dip the authors found at the Fermi level varies with changes in the chemical composition or the crystal structure of the alloy. The singular property of the specific heat of CuAu I can be explained by the lattice contraction in the c direction. Besides these Fermi level properties, the electron density of occupied states, resolved into the total and Au part, is discussed for the case of Cu3Au I, CuAu I and CuAu3. Characteristic d-band energies (top, centre and bottom) are also presented. The calculations were performed using the linear-muffin-tin-orbital method.

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The electronic structure of Ag-Au alloys is studied using LMTO self-consistent band structure calculations. Both, the total and partial density of states as function of Au-content a t the Fermi level are presented. Some results of band structure calculations are analysed using a simple cluster model, which reveals that the behaviour of the partial density of states at the Fermi level can be explained by the s-d hybridisation strength and the position of the top of the d-band. The results obtained for specific heat and spin-lattice relaxation are in general agreement with experimental observations. Furthermore, the calculations predict that the nuclear magnetic spin-lattice relaxation time of Au would decrease with increasing Ag-content.