Light driven Non-Thermal Amorphization Mechanism of Phase Change Material
ORAL
Abstract
Phase-change materials (PCM) are exploited in modern electronics due to the extreme electro-optical contrast between crystalline and amorphous states. However, atomistic mechanisms governing photoexcitation-induced athermal amorphization processes are still unknown. We perform excited-state dynamics within the framework of density functional theory to understand the mechanism behind such crystalline-to-amorphous transition for Germanium Telluride (GeTe). Amorphous phase induced due to excited-state dynamics was characterized by computing diffraction pattern. Further analysis of bond-overlap population shows charge transfer of electron from Ge-Te bonding orbitals to Ge-Ge antibonding orbitals. Such charge transfer process leads to the destabilization of GeTe crystals, eventually leading to amorphization. Rapid heat extraction during excited-state simulation does not lead to amorphous phase. Since structural transformation limits the lifetime of PCM-based devices, a complete understanding behind mechanism may allow us to a new avenue to design better devices.
*This work was supported as part of the Computational Materials Sciences Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award Number DE-SC0014607
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Presenters
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Subodh Tiwari
- Univ of Southern California
- Collaboratory for Advanced Computing and Simulations, University of Southern California