We study from first principles the optical properties of the phase change materials Ge2Sb2Te5 (GST), GeTe and Sb 2Te3 in the crystalline phase and in realistic models of the amorphous phase generated by quenching from the melt in ab initio molecular dynamics simulations. The calculations reproduce the strong optical contrast between the crystalline and amorphous phases measured experimentally and exploited in optical data storage. It is demonstrated that the optical contrast is due to a change in the optical matrix elements across the phase change in all the compounds. It is concluded that the reduction of the optical matrix elements in the amorphous phases is due to angular disorder in p-bonding which dominates the amorphous network in agreement with previous proposals (Huang and Robertson 2010 Phys. Rev. B 81 081204) based on calculations on crystalline models. © 2010 IOP Publishing Ltd.

Caravati, S., Bernasconi, M., Parrinello, M. (2010). First principles study of the optical contrast in phase change materials. JOURNAL OF PHYSICS. CONDENSED MATTER, 22(31), 315801 [10.1088/0953-8984/22/31/315801].

First principles study of the optical contrast in phase change materials

BERNASCONI, MARCO;
2010

Abstract

We study from first principles the optical properties of the phase change materials Ge2Sb2Te5 (GST), GeTe and Sb 2Te3 in the crystalline phase and in realistic models of the amorphous phase generated by quenching from the melt in ab initio molecular dynamics simulations. The calculations reproduce the strong optical contrast between the crystalline and amorphous phases measured experimentally and exploited in optical data storage. It is demonstrated that the optical contrast is due to a change in the optical matrix elements across the phase change in all the compounds. It is concluded that the reduction of the optical matrix elements in the amorphous phases is due to angular disorder in p-bonding which dominates the amorphous network in agreement with previous proposals (Huang and Robertson 2010 Phys. Rev. B 81 081204) based on calculations on crystalline models. © 2010 IOP Publishing Ltd.
Articolo in rivista - Articolo scientifico
Simulazioni da principi primi, semiconduttori
English
2010
22
31
315801
315801
none
Caravati, S., Bernasconi, M., Parrinello, M. (2010). First principles study of the optical contrast in phase change materials. JOURNAL OF PHYSICS. CONDENSED MATTER, 22(31), 315801 [10.1088/0953-8984/22/31/315801].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/17431
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