Ph.D Student | Prus Oleg |
---|---|

Subject | An Experimental Study of the Thermodynamics of Strongly Correlated Two-Dimensional Fermions |

Department | Department of Physics |

Supervisors | Professor Uri Sivan |

Professor Michael Reznikov |

The aim of this work is to
investigate the role of Coulomb interactions in the thermodynamic properties of
two dimensional electron and hole gases . Holes in GaAs/AlGaAs heterostructures
and electrons in Si Metal-Oxide-Semiconductor structures were chosen for the
experiments. The common property of these two dimensional fermion gases is the
strong Coulomb interaction between particles, characterized by the ratio _{} between the
potential energy, associated with the Coulomb interactions, and the particles
kinetic energy. This ratio varied in the experiments described here between 1
and 10.

Compressibility measurements of two dimensional hole gases
(2DHG) in GaAs/AlGaAs heterostructures were carried out by the three plate
capacitor method over a wide temperature range, _{}. The results show a large
negative, and almost temperature independent interaction contribution to the
inverse compressibility. The zero temperature STLS numerical algorithm was
extended to finite temperatures and aaplied to calculate the inverse
compressibility as a function of the carrier density and temperature. A
remarkable agreement between the experiments and the calculations was found.

The central part of this
thesis concerns the magnetic properties of 2DEG by a novel direct method for measuring
the derivative _{}of the magnetization _{}with respect to
density _{}.
The method enabled us to obtain the magnetization by integrating _{} with respect
to density. We found full electron polarization at sufficiently large fields.
No ferromagnetic instability was found in the whole parameter space studied in
the experiment (_{} and _{}). The magnetic susceptibility was
found to be substantially enhanced by interactions.