Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 22: Two-dimensional materials III (jointly with HL/TT)

DS 22.10: Talk

Tuesday, March 21, 2017, 12:30–12:45, POT 51

ab initio study of the transport properties in bulk and monolayer MX₃ (M = Ti, Zr, Hf and X = S, Se) compounds. — •Yasir Saeed — Qatar Environment and Energy Research Institute (QEERI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, P.O. Box 5825, Doha, Qatar

Two dimensional (2D) materials are best candidates for thermoelectric application due to their low thermal conductivity which is key property to achieve high efficiency for their usage in the filed of energy harvesting. Owing to that, here we present a study on electronic as well as thermal transport of bulk and monolayer MX₃ compounds (M = Ti, Zr, and Hf and X = S and Se) are investigated by by density functional theory and semi-classical Boltzmann theory. The bandgap amounts to rather similar value for bulk and monolayer, only the shape of band near Fermi level changes slightly, which results in a modified effective mass. We found that monolayer MX₃ compounds are good TE materials than bulk. Also p-type monolayer TiS₃ has twice large PF at 600 K than its room temperature value. However, monolayer Zr/HfSe₃ compounds showing promising behavior as a n-type TE materials at elevated high temperature of 600 K. In-plane tensile strain is also possible to tune the bandgap to increase S and disorder the monolayer lattice to minimize κ, therefore turns out to be a highly efficient approach for creating high performance TE materials.