ELFT HÍRADÓ

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

Az ELTE Nanofizika Szeminarium jovo hetfoi eloadasa:


Makk Peter (Basel): Electron optics in Graphene from Snake States to Electron 
Guiding

Idopont: 2014. majus 26., hetfo, 10:15
Helyszin: ELTE Eszaki Tomb, 5.128-as terem (1117 Budapest, Pazmany Peter 
setany 1/A)

Kivonat:
"We have fabricated suspended monolayer graphene devices on organic lift-off 
resists. We have extended this technology, which was introduced by N. Trombos 
et al. in 2011 [1], allowing to add a multitude of bottom and top gates . 
Recently we have demonstrated that with this technique a ballistic p-n 
junction can be created and intriguing Fabry-Perot oscillations were observed 
from the electrons localized in the cavities formed by local gates. We will 
go beyond our recent publication [2] and also show transport measurements in 
magnetic field, where striking features appear. Since these measurements on 
the p-n junction are in the completely ballistic regime they display novel 
behavior from the previous results on diffusive junctions [3]. We observe a 
large number of resonances in the bipolar regime, which are related to 
snaking trajectories along the p-n interface. The theoretical calculations 
clearly reproduce the  measured features, and the simulated current density 
plots give further insight to the nature of the conductance oscillations. 
Using the great versatility of our fabrication method, we also developed a 
four terminal suspended device allowing us to study electron guiding in 
ultraclean monolayer graphene. We will show, that the electrons can be guided 
by gate potentials the same way than photons in an optical fiber, and that 
the formation of a p-n interface increases the guiding efficiency due to 
Klein filtering. 

References 
[1] N. Tombros et al., Journal of Applied Physics 109, 093702 (2011). 
[2] P. Rickhaus et al., Nature Communications , 4, 2342 (2013) 
[3] J.R. Williams et al., Science 317, 638 (2007)"


Minden erdeklodot szivesen latunk.

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

Udvozlettel,
Palyi Andras