Mechanical response of aluminum nanowires via orbital-free density functional theory

Thin aluminum nanowires of widths 0.3 nm to 6.0 nm are investigated using orbital-free density functional theory. Predictions of the minimum energy structures of ultrathin aluminum nanowires as a function of the one-dimensional atomic density are given. Quasistatic orbital-free density functional theory calculations suggest that thin aluminum nanowires of bulk face-centered cubic morphology originally oriented in the [001] direction may undergo a transition to either a body-centered tetragonal [001] or a face-centered cubic [110] orientation under compression. The stable body-centered tetragonal [001] wire is almost 30% shorter than the original stable face-centered cubic [001] wire. The relative stability of the two states is tunable by varying the size of the nanowires. It may be possible to switch the state of the nanowire by uniaxial compression and expansion, leading to applications as a nanoscale actuator or switch.