First year PhD talk - Markus Kotulla
Talk title: 'Confined 3D Topological Insulator'
Speaker: Markus Kotulla, PhD candidate, supervised by Prof Uli Zuelicke, SCPS
Recent discoveries have led to the theoretical prediction  and experimental realization  of novel materials that have topological properties arising from band inversion, which occurs when anti-bonding states are forming the valence band while bonding states are the conduction band. These so called Topological Insulators are insulating in the bulk but have conductive surface or edge states. Topological materials show various unusual physical properties and are surmised to enable the creation of exotic Majorana-fermion quasiparticles .
Based on the effective-Hamiltonian description of 3D-bulk Topological insulators , we have studied the interplay of band inversion and quantum confinement . Unlike previous related studies [6,7,8], we use a harmonic-oscillator potential as confinement of the 3D Topological-Insulator sample. As illustrated in Fig. 1, our model system provides a useful platform for systematic study of the transition between the normal and topological insulating phases, including the development of band inversion, the effects of particle-hole asymmetry, and gap oscillations.
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