Abstract :
[en] Recently, nanostructuration has been proposed to improve the performance of phase change memories. This is the case of superlattices composed of amorphous carbon and crystalline germanium telluride, which we have investigated by molecular dynamics. For this, a modified Stillinger-Weber potential is adapted to reproduce their stiffness contrast/impedance ratio. In order to study the effect of the interface interaction, two sets of parameters are used to model the interfaces with different interactions between the two materials using the properties of the softer material or the average properties between the two creating an adaptation of impedance across the layers. The effects of interface roughness and carbon diffusion at grain boundaries are studied. Using equilibrium molecular dynamics as well as the propagation of wave-packets, we show first that without impedance adaptation, the anisotropy is high, and the roughness has a marked impact on the properties. However, the introduction of impedance adaptation destroys those effects on the thermal conductivity. Finally, we show that the periodic texturing of the interface increases the transmission of in-plane transverse phonons.
Funding text :
This work was granted access to the HPC resources of IDRIS under the allocation 2021- A0110911092, made by GENCI. This research was funded by ANR under the contract MAPS ANR-20-CE05-0046-03 and from the AURA region for the NanoCHARME project. The authors also thank the CNRS for funding the mobility of J.-Y.R. to Lyon through the Dialogue program. The authors want to thank fruitful discussions with Anne Tanguy.
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