Topological Superconductivity

Details : The quantum Hall(QH) insulator—the first 2D topological insulator discovered— supports a set of chiral conducting states at the edge of the system. Recently, this hybrid QH/superconductor(SC) system has received renewed attention as a novel route to realize non-Abelian zero-energy modes such as parafermionic zero modes—generalized Majorana zero modes. This system is of great interest because (i) the parafermionic modes allow bona fide topological quantum computation without resorting to non-topological quantum computers (Fig. 4), and (ii) the 2D nature of the system can facilitate flexible topological braiding operations with in-situ electrostatic gate controls. Despite these strong advantages and the intensive theoretical investigations on the hybrid QH/SC system, experimental development is still at a preliminary stage. Only recently, superconducting coupling of the counter-propagating QH edge states in graphene has been demonstrated at various filling factors (n), including n= 1 where Majorana zero modes are expected to occur[5]. Here, I elaborate on some feasible ideas for investigating topological superconductivity in a hybrid QH/SC structure (Fig. 5).

My Interests :

  1. Observation of zero-energy state of Majorana state in Graphene/Superconductor heterostructure
  2. 'Ultimately' Developing 2-D archetecture of realizing braiding operations
  3. Understadning on Josephson current through quantum Hall edge states

Topologycal Quantum Computer

Fig. 4 | Topological quantum computer with braiding operations [picture from S.J. Lomonaco]


Fig. 5 | Van der Waals structure for studying Topological superconductivity

[5] Gil-Ho Lee et al.Nature Phys. (2017) doi:10.1038/nphys4084


GHLee Lab