First year PhD talk - Markus Kotulla

First year PhD talk - Markus Kotulla

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2 May 2017 from 12.00 pm 2nd May 2017 12:00pm

LB408, Laby Building

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 [1] and experimental realization [2] 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 [3].Confined 3D Topological Insulator

Based on the effective-Hamiltonian description of 3D-bulk Topological insulators [4], we have studied the interplay of band inversion and quantum confinement [5]. 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.


  1. C. L. Kane and E. J. Mele,  Phys. Rev. Lett. 95, 226801 (2005).
  2. M. König et al., Science 318, 766 (2007).
  3. L. Fu and C. L. Kane, Phys. Rev. Lett. 100, 096407 (2008).
  4. H. Zhang et al., Nat. Phys 82, 438, (2009).
  5. M Kotulla and U Züelicke, preprint arxiv:1703:09356
  6. W.-Y. Shan, H.-Z. Lu, and S.-Q. Shen, New J. Phys. 12, 043048 (2010).
  7. J Linder, T Yokoyama, and A Sudbø. Phys. Rev. B 80, 205401 (2009)
  8. C X Liu et al., Phys. Rev. B 81, 041307