Thermal Transport of Novel Two-dimensional Silicon

• Applicant: Professor Dr. Ming Hu
• Subject Area: Theoretical Condensed Matter Physics ; Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 267464562

Graphene, a two-dimensional atomic thin honeycomb lattice, exhibits numerous striking physical properties, and can, in principle, be considered as an elementary building block for all carbon allotropes. Ever since the recent developments in 2004, the field of graphene research took off rapidly. These developments in the science of graphene prompted an unprecedented surge of activity and demonstration of new physical phenomena. Despite its success, graphene still faces some severe problems in its nature of semi-metal or zero band-gap semiconductor and its incompatibility with the current Si-based technology. Given that the honeycomb geometry is related to some of the exceptional properties of graphene, there is strong motivation to investigate whether changing carbon to other atom type might give rise to novel physical phenomena as well. An intuitive idea is to study its analog - silicene. Acutally, silicene, the Si counterpart of graphene, can solve the above problems smoothly and thus has received intense interest lately. Given the fact that thermal transport plays a critical role in many applications such as heat dissipartion in nanoelectronics and thermoelectric energy conversion, there has been an emerging demand in characterizing thermal (mainly phonons) transport property of silicene structures. Moreover, our preliminary results have shown that silicene exhibits a few novel thermal transport properties, which are fundamentally different from that of graphene, despite the similarity of their honeycomb lattice structure. Therefore, the abnormal physical property, primarily stemming from its unique low buckling structure, may enable silicene to open up entirely new possibilities for revolutionary electronic devices and energy conversion materials. With this state of the art, the current proposal aims to perform theoretical investigations of thermal transport of silicene nanostructures in various forms. Heat transfer in such structures is not only directly relevant to optimizing the relevant device performance such as improved thermal management for nanoelectronics and thermoelectric energy conversion efficiency, but also is a scientifically fundamental problem for many other similar two-dimensional systems. The overall objective of this proposal is to advance the fundamentals underlying the thermal transport of silicene structures as novel two-dimensional material for emerging technologies. Closely linked and interdependent classical molecular dynamics simulations and ab initio based nonequilibrium Greens function and combined anharmonic lattice dynamics and Boltzmann transport equation are proposed as approaches to this end. The investigation is likely to provide a major advancement to the fundamental understanding of thermal transport mechanism of silicene and more broadly two-dimensional materials, with the potential to make a clear contribution to development of high performance nanoelectronics and the energy needs of the future.

• DFG Programme: Research Grants