[seminar] podsjetnik na DANASNJI seminar na IF-u u 15:00

[Berislav Horvatic]

Poštovani,
podsjećamo Vas na današnji seminar na 
Institutu za fiziku u 15:00 sati:




       

      Institut za fiziku, Bijenička cesta 46,

      predavaonica u zgradi Mladen Paić

      utorak, 19. travnja 2011, u 15:00 sati

       
     
      Aspects of Nonequilibrium Physics:

      Quantum Hall effect

       
     
      Dr. Christoph Uiberacker
     
       

      Montanuniversität Leoben, Institut für Physik,

      Franz-Josef-Straße 18, 8700 Leoben, Austria

       

      E-mail: christoph.uiberacker at unileoben.ac.at

       
     
      The Nonequilibrium Network Model (NNM) [1,2] describes the electrochemical potential in 2d electron systems by using the Landauer-Büttiker approach. The chemical potential distribution is obtained, for linear local response, from an inhomogeneous system of linear equations, respecting the potential boundary condition from injected currents. We show that the construction of the network guarantees current conservation even in the nonlinear transport regime.

      Due to the lack of simulation tools for realistic geometries of complicated quantum Hall samples there are experiments that are not fully understood yet. Already some years ago R. G. Mani recorded a shift of the Hall resistance transitions using partial gating of a sample consisting of an anti-Hall bar within a Hall bar. Using the NNM we find qualitative agreement. By fitting to the experimental Hall resistance we reproduce the carrier concentration, the bare gating voltage in the 2d electron gas and the curvature of saddles points. Using a simple statistical argument by Gerhardts [3] we can estimate the magnitude and correlation length of the potential from charge fluctuations in the 2d electron gas.

      [1]      J. Oswald and M. Oswald, "Circuit type simulations of magneto-transport in the quantum Hall effect regime", J. Phys.: Condens. Matter 18, R101 (2006)

      [2]      C. Uiberacker, C. Stecher, and J. Oswald, "Systematic study of nonideal contacts in integer quantum Hall systems", Phys. Rev. B 80, 235331 (2009)

      [3]      J. Oswald and C. Uiberacker, "Gate Controlled Narrowing of the Quantum Hall Effect Plateau Transitions", J. Phys.: Conf. Ser. 200, 012153 (2010)

      [4]      U. Wulf, V. Gudmundsson, and R. R. Gerhardts, "Screening properties of the two-dimensional electron gas in the quantum Hall regime", Phys. Rev. B 38, 4218 (1988)

       

      http://personal.unileoben.ac.at/oswald/nipi/nipihome.htm

       
     
      Voditelji seminara IF-a:  Berislav Horvatić  &  Ivica Živković



      http://www.ifs.hr/Seminar.aspx?id=91
     
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.phy.hr/pipermail/seminar/attachments/20110419/1f6511cd/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 5380 bytes
Desc: not available
URL: <http://www.phy.hr/pipermail/seminar/attachments/20110419/1f6511cd/attachment-0001.jpeg>