title: Nuclear-relaxed elastic and piezoelectric constants of materials: Computational aspects of two quantum-mechanical approaches.
abstract: Two alternative approaches for the quantum-mechanical calculation of the nuclear-relaxation term of elastic and piezoelectric tensors of crystalline materials are illustrated and their computational aspects discussed: (i) a numerical approach based on the geometry optimization of atomic positions at strained lattice configurations and (ii) a quasi-analytical approach based on the evaluation of the force- and displacement-response internal-strain tensors as combined with the interatomic force-constant matrix. The two schemes are compared both as regards their computational accuracy and performance. The latter approach, not being affected by the many numerical parameters and procedures of a typical quasi-Newton geometry optimizer, constitutes a more reliable and robust mean to the evaluation of such properties, at a reduced computational cost for most crystalline systems. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Centre of Excellence, Via Giuria 5, Torino, 10125, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Erba
authors.affiliation: Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Centre of Excellence, Via Giuria 5, Torino, 10125, Italy.
authors.forename: Dominique
authors.initials: D
authors.lastname: Caglioti
authors.affiliation: Centro de Investigación en Ciencias-(IICBA), Universidad Autónoma del Estado de Morelos, Av. Universidad, 1001, Col. Chamilpa, Cuernavaca, Morelos, 62209, Mexico.
authors.forename: Claudio Marcelo
authors.initials: CM
authors.lastname: Zicovich-Wilson
authors.affiliation: Dipartimento di Chimica, Università di Torino and NIS, Nanostructured Interfaces and Surfaces, Centre of Excellence, Via Giuria 5, Torino, 10125, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Dovesi
keywords: elasticity; piezoelectricity; strain tensor