Ph.D Thesis

Ph.D StudentNimrod Teneh
SubjectSpin-Droplet State of an Interacting 2D Electron System
DepartmentDepartment of Physics
Supervisor Professor Reznikov Michael
Full Thesis textFull thesis text - English Version


Low-dimensional electron systems are of fundamental interest due to a wide range of fascinating phenomena featured by these systems, in addition to many possible applications in nano-electronics. However, some important properties of these systems remain beyond the reach of conventional methods due to small number of electrons.

Recently, a novel technique for measuring magnetic properties of such systems was developed in our group. This technique senses the charge induced in response to a change of external magnetic field. Its sensitivity compares favorably with that of the best available magnetic probes. It has the advantage of being naturally suited for measurements of two-dimensional systems, and it is capable of working in the wide range of magnetic fields.

In this thesis we report thermodynamic magnetization measurements of two-dimensional electrons in several high mobility Silicon Metal-Oxide-Semiconductor Field-Effect Transistors and a single GaAs/AlGaAs Heterostructure Insulated Gate Field Effect Transistor. We provide evidence for an easily polarizable electron state in a wide density range from insulating to deep into the metallic phase. The temperature and magnetic field dependence of the magnetization of this state is consistent with formation of large-spin droplets in the insulating phase. Although these droplets melt in the metallic phase with increasing density and temperature, they survive up to relatively large densities, that is densities above the Metal Insulator Transition (MIT) critical density.