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SUMMARY:Hubbard-Mott physics of electrons in an artificial semiconductor l
 attice - Vittorio Pellegrini (NEST Instituto Nanoscienze-CNR)
DTSTART:20101018T143000Z
DTEND:20101018T160000Z
UID:TALK27053@talks.cam.ac.uk
CONTACT:6270
DESCRIPTION:In this talk I’ll discuss recent optical and transport resul
 ts obtained in a high-mobility two-dimensional electron gas confined in a 
 GaAs quantum well and subjected to a lateral potential with honeycomb topo
 logy [1\,2\,3]. By tuning the properties of the honeycomb lattice with a g
 ate voltage and a magnetic field we were able to drive the system into loc
 alized or delocalized transport regimes. In this latter case we probed the
  cyclotron spectrum by means of inelastic light scattering and we identifi
 ed a novel low-lying excitation at high magnetic fields with unexpectedly 
 large oscillator strength. I will argue in the talk that this new gapped m
 ode is a direct manifestation of the modification of the excitation spectr
 a predicted by the Hubbard model [4]. Since the Hubbard model underpins th
 e essential physics of Mott insulators\, our approach offers new venues fo
 r experimental simulation of quantum phenomena in a controllable solid-sta
 te systems.\n\n* work done in collaboration with A. Singha\, M. Gibertini\
 , M. Polini\, B. Karmakar\, G. De Simoni\, A. Pinczuk\, G. Vignale\, L.N. 
 Pfeiffer\, K.W. West\n\n[1] M. Gibertini et al. Phys. Rev. B RC 79\, 24140
 6 (2009)\n\n[2] G. De Simoni et al. arXiv:1007.3168\n\n[3] A. Singha et al
 . in preparation\n\n[4]  J. Hubbard. Proc. R. Soc. Lond. A 281\, 401 (1964
 )\n\n
LOCATION:Rutherford building\, Seminar Room B
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