Thursday's seminar

[CM]

SEMINAR on    Disorder and strong electron correlations



Thursday, 14 May      -  11:00 a.m.



Seminar Room,  Leonardo Building - first floor



Markus MÜLLER    ( The Abdus Salam ICTP )



"Relativistic transport in clean graphene -  a nearly perfect quantum 
liquid"


Abstract


The electrons and holes in a graphene sheet behave very much like a 
relativistic liquid. As a consequence, the properties of thermo-electric 
transport of this fluid of interacting Dirac fermions are rather 
peculiar.  At small doping and high temperatures, graphene exhibits many 
signatures of a quantum critical system: the inelastic scattering rate 
is set only by the temperature, and the conductivity assumes a nearly 
universal value, solely due to electron-hole friction.  In this regime 
we find pronounced deviations from standard Fermi liquid behavior and a 
peculiar collective cyclotron resonance in the frequency dependent 
response.  Some of these results have been anticipated by a relativistic 
hydrodynamic theory, and are fully confirmed by Boltzmann transport 
theory for weak coupling.  Most interestingly, similar results are also 
found in the case of certain strong coupled liquids which can be solved 
exactly by the AdS-CFT correspondence.  Moreover, in that context it is 
interesting that undoped graphene turns out to be a nearly ideal fluid 
with an anomalously small electronic viscosity, very similar to recent 
observations in the ultra-relativistic quark gluon plasma. I will also 
discuss possible consequences of the low viscosity for electronic 
transport in clean graphene.