Семинар лаборатории теоретической физики

В пятницу, 16 мая, в 10-00 в к. 247 ЛТК состоится семинар лаборатории теоретической физики.

А.Д. Шепелянский

Incompressible state of photo-excited electrons on the Helium surface

A.D. Chepelianskii, M. Watanabe, D. Konstantinov, K. Kono

LPS, Univ. Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex, France Low Temperature Physics Laboratory, RIKEN, Hirosawa 2-1, Wako 351-0198, Japan Okinawa Institute of Science and Technology, Tancha 1919-1, Okinawa 904-0412, Japan

Abstract :
Two dimensional electrons in a magnetic field can form new states of matter characterized by topological properties and strong electronic correlations such as in the integer and fractional quantum Hall states. In these states the electron liquid displays several spectacular characteristics which manifest themselves in the linear response regime with the quantization of the Hall resistance and a vanishing longitudinal conductivity, or directly in thermodynamic equilibrium when the electron fluid shows an incompressible behavior. Several experiments have reported that dissipation-less transport can be achieved even at weak non-quantizing magnetic fields when the electrons absorb photons at specific energies related with their cyclotron frequency. We performed compressibility measurements on photo-excited electrons on liquid Helium demonstrating the formation of a new incompressible electronic state under resonant excitation conditions. Contrarily to the quantum Hall effect where a non-equilibrium electron density distribution becomes meta-stable due to the vanishing conductivity, we show that the incompressible behavior of excited electrons on Helium originates from the pinning of the electron density to a fixed value independent on the initial conditions. This newly discovered state offers a striking example of irradiation induced self-organization in a quantum system.