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Interactions effects in weakly confined quasi one-dimensional quantum wire

Montagu, HEW; (2016) Interactions effects in weakly confined quasi one-dimensional quantum wire. Doctoral thesis , UCL (University College London). Green open access

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Abstract

Since the initial realisation of split-gate device and quantised plateaus of conductance in one-dimensional quantum wires, there has been immense interest in studying transport through one-dimensional electron systems to investigate many-body effects. This thesis contains results of experiments performed on novel discrete quantum devices with potential for tuning the confinement as well as the electron density to investigate many-body effects and electron-electron interactions in weakly confinement quantum wires. This thesis covers a detailed development of technology for fabricating novel discrete quantum devices consisting of mid-line, top and back gates patterned along with standard split-gates devices. A novel mid-line gated, split gates device demonstrates the possibility of creation of two lateral one-dimensional quantum wires in a single two-dimensional electron gas (2DEG). This allows the systematic investigation of interaction effects between the quantum wires. Several measurements are performed to further characterise such laterally created quantum wires system in detail. It is also shown that the two one-dimensional quantum wires created out of a single 2DEG exhibit finite coupling between them as a function of mid-line gate thickness. This coupling manifested itself through crossing and anti-crossing of the subbands. The thesis also covers experimental investigations performed on a weakly confined, low-density quasi-one-dimensional system which was achieved by developing novel back-gated split-gate devices. The thesis presents the possible experimental evidence of two interaction phenomena which occur in the low-density regime such as spontaneous spin polarisation and spin-incoherent transport in one-dimensional quantum wires. The experimental evidence of spin-incoherent transport can be seen in the form of a conductance plateau at 0.5(2e^2/h) at very low electron density, whereas the spontaneous spin polarisation shows an additional plateau at 0.5(2e^2/h) along with plateau (2e^2/h). The experimental results presented in the thesis give an important insight and advances in the research of many-body physics in one-dimensional quantum wires.

Type: Thesis (Doctoral)
Title: Interactions effects in weakly confined quasi one-dimensional quantum wire
Event: UCL (University College London)
Open access status: An open access version is available from UCL Discovery
Language: English
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/1521719
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