The phase diagram and electronic structure of Pd-V alloys: ab initio density functional calculations

A parameter-free approach based on nb initio density functional calculation s is shown to describe the phase stability and order-disorder transformatio ns in Pd-V substitutional alloys and intermetallic compounds with remarkabl e accuracy, allowing first-principles calculations of the complete alloy ph ase diagram. The investigations are based on electronic structure and total -energy calculations for ordered compounds and disordered alloys (treated i n a supercell approximation) using gradient-corrected exchange-correlation functionals and a plane-wave-based all-electron method. All calculations in volve a complete optimization of all structural degrees of freedom. The cal culation of the free energies of the competing phases is based on rather si mple mean-held descriptions of long- and short-range-ordering phenomena, us ing concentration-dependent interchange and shell interaction parameters. I n addition, the electronic structures of ordered compounds and of substitut ional alloys have been analysed.