| Summary: | 碩士 === 國立成功大學 === 物理學系 === 104 === There have been many studies of non-interacting one-dimensional system which can be created from two-dimensional electron gas by applying electrostatic confinement which is provided by a voltage applied to split gates. At low electron density, Coulomb potential dominate over the kinetic energy. In order to minimize the Coulomb repulsion, electrons occupy equidistance positions, forming a Wigner crystal. With increasing electron density in Wigner crystal regime, transforming the one-dimensional Wigner crystal into a staggered zig zag chain. Former research has shown that sufficiently strong interaction give rise to a ferromagnetic ground state.
In this thesis, we designed a device based on magnetic focusing geometry. The device contains a top gate and split gates which can be utilized to control the electron density and electrostatic confinement. By applying transverse magnetic field, the focusing peaks gradually evolve from single peak to two peaks when we tune the electrostatic confinement and carrier density. Through the magnetic focusing, we can detect the arrangement of electron in real space. Furthermore, we apply source-drain bias to our device, so we can detect the spin properties in one-dimensional system. In strongly interacting regime, the focusing peaks rise because of the spin polarization in strongly interacting regime. In addition, the peaks barely change in the weakly interacting regime. Our experiment provide a method to detect the arrangement of electrons and detect the spin dynamic in one-dimensional system.
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