| 报告题目： |
First principles calculations of electron transport in graphene nano-structures |
| 报告人： |
Mads Brandbyge |
| 报告人单位： |
Technical University of Denmark, DTU Nanotech, Kgs. Lyngby, Denmark Center for Nanostructured Graphene (CNG) |
| 报告时间： |
2018年4月20日（周五）下午16:00 |
| 报告地点： |
科技楼北410会议室 |
| 报告摘要： |
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Devices based on stacked van der Waals heterostructures of two-dimensional (2D) materials are promising candidates for future atomically thin, flexible electronics with properties that can be tuned by the electrostatic and dielectric environment. One of the key advantages of two-dimensionality is that it allows very precise control of the carrier density and voltage drop by a gate potential. However, the application of the gate potential may not only influence the transport via the carrier density in simple ways.
In this talk we present examples where we employ first principles transport calculations based on Density Functional Theory (DFT) which explicitly include the electrostatic gate potential and induced carriers. DFT is combined self-consistently with non-equilibrium Greens functions to study the effects of finite bias in devices, or as input to the Boltzmann equation to study bulk conductivity.
We consider the role of the gate geometry for the contact resistance in a stacked device where graphene is used as electrode to a MoS2 channel. We show how the contact resistance depends critically on the stacking configuration and establish a design rule for the stacking of devices based on 2D materials.
We also consider how the gate potential can induce a new flexural phonon scattering mechanism in a graphene device where gating can break the planar mirror symmetry activating one-phonon scattering from flexural phonons. |
| 报告人简介： |
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Mads Brandbyge教授于1994年和1997年分别在哥本哈根大学和丹麦技术大学获得硕士和博士学位。1997-1998年在东京大学从事博士后研究。1998年至今在丹麦技术大学先后任助理教授、副教授和教授。Brandbyge教授的研究兴趣为纳米电子器件中的电、热输运性质的第一性原理计算及相关计算方法的发展。他将基于密度泛函理论的电子结构计算与非平衡输运理论相结合，开发出了现在被学界和工业界广泛应用的量子输运计算程序TransSIESTA，其商业版本由Synopsis下属的QuantumWise公司负责销售。近年来，他的主要研究对象为以石墨烯为代表的二维材料中的输运性质。 |
