22.11.2019 - Oguz Gulseren : Temperature Dependent Phonon Spectrum of Novel 2D Materials

Temperature Dependent Phonon Spectrum of Novel 2D Materials

Oguz Gulseren
Department of Physics, Bilkent University, Ankara
22 November 2019, Friday, 14:40
Cavid Erginsoy Seminar Room, Physics Department, 3rd floor

Abstract: Lattice Thermal Conductivity as an Application Two-dimensional materials are expected to become key components for novel applications because of their exotic properties. Although, rigorous density functional theory based calculations are able to predict mechanical and electronic properties, mostly they are limited to zero temperature. Classical molecular dynamics facilitates the investigation of temperature dependent properties, but its performance highly depends on the potential used for defining interactions between the atoms. In this study, we calculated temperature dependent phonon properties of several single layer 2D systems including graphene, silicene, group III nitrides, i.e GaN, AlN and BN, and TMDs by developing particle swarm optimized Stillinger-Weber type potentials with respect to the first-principles datasets. These potentials validated by comparing the resulted phonon dispersion curves and thermal conductivities with available first-principles and experimental results. The phonon lifetimes and contribution of each phonon mode in thermal conductivities in these monolayer crystals are systematically investigated by means of spectral energy density method based on molecular dynamics simulations.