Quantum study of tungsten interaction with beryllium (0001)

Beryllium, tungsten and carbon are planned as wall materials for the future international tokamak (ITER). Be and W will be the dominant components and therefore the formation of binary Be-W alloys under plasma action is one of the most important issues in plasma-wall interaction processes at the first wall. The formation of alloys and their reactivity under physical sputtering and chemical erosion constitute a new challenge for solid states physics and chemical reactivity. This article proposes a theoretical study of the first stages of the formation of these alloys based on the first principles DFT method. The tungsten adsorption energy on the basal (0001) beryllium surface is first calculated, and then the barrier to retention into the bulk. For each calculation the electronic structure of the formed compound is analyzed through density of states (DOS) calculation. The results are discussed with respect to experimental observations during the formation of a Be12W alloy layer and changes in the electronic structure of Be during alloying, observed in shifts of the Be 1s core levels.