Purdue University

Department of Physics
Condensed Matter Seminar

Electronic origin of the kinetics and dynamics of atoms on vicinal metal substrates*

Friday December 03, 2010

Refreshments are served at 3:00 p.m. in Physics room 242.

Zhenyu Zhang

Materials Science and Technology Division, Oak Ridge National Laboratory & Department of Physics and Astronomy, The University of Tennessee

http://www.phys.utk.edu/cmp/cmp_people_zhang.htm

  The kinetics and dynamics of atoms near monatomic-layer-high steps play a decisive role in the morphological evolution at surfaces via nonequilibrium growth [1]. In this talk, I will attempt to give a comprehensive view on the trends of step-edge barriers as different metal atoms of varying electron shell filling descend at step edges [2]. I will also discuss how the different electronic bonding strengths influence the nucleation and growth behavior of carbon atoms at step edges [3], as well as how such electronic degrees of freedom contribute to atomic rate processes within the context of electromigration [4]. The insights gained through these first-principles studies have timely and important impacts in understanding the evolution of many nanostructured surfaces, including the nucleation and growth of metal atom wires [5] and epitaxial graphene [6,7], and prevention of electrical breakdown in nanodevices. Timing permitting, I will speculate on a few kinetic pathways that may lead to better control of bilayer graphene and graphene nanoribbons as elemental building blocks for developing graphene electronics.

*Supported by USDOE, USNSF, and NNSF of China, and in collaboration with the authors listed below.

[1] Z. Y. Zhang and M. G. Lagally, Science 276, 377 (1997).

[2] Y. N. Mo, W. G. Zhu, E. Kaxiras, and Z. Y. Zhang, Phys. Rev. Lett. 101, 216101 (2008).

[3] H. Chen, W. G. Zhu, and Z. Y. Zhang, Phys. Rev. Lett. 104, 186101 (2010); R. van Wesep et al., to be published.

[4] K. H. Bevan, W. G. Zhu, H. Guo, and Z. Y. Zhang, Phys. Rev. Lett. (submitted).

[5] Y. N. Mo, K. Varga, E. Kaxiras, Z. Y. Zhang, Phys. Rev. Lett. 94, 155503 (2005).

[6] Q. K. Yu, et al., Appl. Phys. Lett. 93, 113103 (2008).

[7] X. S. Li, et al., Science 324, 1312 (2009).