ELFT HÍRADÓ

[Balazs Dora <dora AT kapica.phy.bme.hu>]

2010. majus 26-an 10 orai kezdettel Eduardo V. Castro eloadast tart a BME 
Fizika Tanszeken (F. epulet, 2. emelet, 13-as labor) "Temperature 
dependent resistivity in doped suspended graphene: the role of phonons"
cimmel

ABSTRACT: The scattering mechanism which ultimately limits mobility at 
room temperature in graphene is of utmost importance from the point of 
view of applications. From a more fundamental point of view unveiling
such mechanism should provide important clues to understand this 
fascinating system. Recently, suspended graphene samples were shown to 
have mobilities higher by at least 1 order of magnitude than the 
non-suspended ones. The reported big numbers, however, show up only at low 
temperatures; at room temperature mobility falls into the values reported 
for non-suspended samples. When the system is suspended acoustic phonons
should be the ultimate scatterers determining the temperature dependent 
resistivity, and hence mobility. In this talk I will explore the effect of 
flexural phonons -- out-of-plane vibrations of the graphene
membrane -- on the resistivity's temperature dependence of doped suspended 
graphene. It will be shown that flexural acoustic phonons give the major 
scattering contribution at room temperature, and indeed limit mobility to 
values known for samples on substrate. Under strain, however, scattering 
by flexural phonons becomes negligible, thus providing a solution to the 
room temperature flexural phonon limited mobility in doped suspended 
graphene. Moreover, by manipulating locally the induced strain it is
possible to control the current path in real space; an example of strain 
engineering applied to graphene.

Minden erdeklodot szeretettel varunk!

Dora Balazs