Soler, J.M., Artacho, E., Gale, J.D., García, A., Junquera, J., Ordejón, P. and Sánchez-Portal, D. (2002) The SIESTA Method for ab Initio Order-N Materials Simulation. Journal of Physics: Condensed Matter, 14, 2745-2779. https://doi.org/10.1088/0953-8984/14/11/302