Eur. Phys. J. B (2017) 90: 19
https://doi.org/10.1140/epjb/e2016-70391-0

Regular Article

On the photoinduced phase transition from the amorphous to crystalline phase in (GeTe)_n(Sb₂Te₃)_m

¹ NRC “Kurchatov Institute”, 123182 Moscow, Russia
² RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, 351-0198 Saitama, Japan

^a e-mail: seryak56@mail.ru

Received: 22 June 2016
Received in final form: 1 December 2016
Published online: 25 January 2017

Abstract

We suggest a phenomenological description of the photo-conversion in Ge-Sb-Te phase-change memory alloys from amorphous to crystalline tetrahedral phase. Suggested mechanism explains why both photo-excitation and high enough temperatures T > 160 °C are required for the transition from the amorphous to metastable crystalline phase. High energy position of chemical potential at elevated temperatures facilitates light induced creation of stable nucleons of the crystalline phase which are unstable at lower T. Then, light driven population of nucleons leads to accumulation of holes on neighboring Te and Ge ions and locks the photo-conversion transition by pushing Ge ions into the interstitial position to minimize the Coulomb repulsion energy.