ELFT HÍRADÓ

[Andras Palyi <andraspalyi AT caesar.elte.hu>]

Az ELTE Nanofizika Szeminarium jovo hetfoi eloadasa:

Tapasztó Levente (MFA): Nanométeres hullámok a grafén atomi  
szerkezetében

Understanding how the mechanical behaviour of materials deviates at  
the nanoscale from the macroscopically established concepts is a key  
challenge of particular importance for graphene, given the complex  
interplay between its nanoscale morphology and electronic properties.  
In this work, the (sub)nanometre-wavelength periodic rippling of  
suspended graphene nanomembranes has been realized by thermal strain  
engineering and investigated using scanning tunnelling microscopy.  
This allows us to explore the rippling of a crystalline membrane with  
wavelengths comparable to its lattice constant. The observed  
nanorippling mode violates the predictions of the continuum model, and  
evidences the breakdown of the plate idealization of the graphene  
monolayer. Nevertheless, microscopic simulations based on a quantum  
mechanical description of the chemical binding accurately describe the  
observed rippling mode and elucidate the origin of the continuum model  
breakdown. Spatially resolved tunnelling spectroscopy measurements  
indicate a substantial influence of the nanoripples on the local  
electronic structure of graphene and reveal the formation of one- 
dimensional electronic superlattices.

Reference: L. Tapasztó et al., Breakdown of continuum mechanics for  
nanometre-wavelength rippling of graphene, Nature Physics 8, 739–742  
(2012), doi:10.1038/nphys2389

Helyszin: ELTE Eszaki Tomb, 5.55-os terem (1117 Budapest, Pazmany  
Peter setany 1/A),
Idopont: 2012. oktober 29. hetfo, 10:15

Minden erdeklodot szivesen latunk.

A szeminarium tovabbi programja: 
http://wigner.elte.hu/koltai/science/?q=seminar

Udvozlettel,
Palyi Andras