Simulated Annealing of Nanowire Structures using a Quantum-Based Model

We performed simulations of the equilibrium atomic structures of metallic nanowires based on a~classical energy model~which includes~a short-range (phenomenological hard-core) repulsion,~a screened Coulomb potential, and~a quantum-mechanics based potential energy that stabilizes longer wires. We simulated cylindrical sodium nanowires~with "magic" radii, on order of Angstroms, predicted to be stable by the nanoscale free electron model. The boundary conditions are chosen to simulate a wire connected to bulk contacts. Written in C,~our program is based on a Monte-Carlo simulated annealing algorithm and utilizes the double precision SIMD oriented Fast Mersenne Twister (dSFMT) pseudo-random number generator. The simulations performed found that the atoms arrange themselves in multi-shell helical structures.