Yeongjun Kim

PCS IBS (Comprehensive Exam)

28 March 2023 Tue 3 pm

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

We consider manifolds of tunable all-bands-flat (ABF) lattices in dimensions d=1,2, parametrized by a manifold angle parameter theta. We study localization properties of eigenstates in the presence of weak magnetic flux disorder and weak spin-orbit disorder. We demonstrate that weakly disordered ABF lattices are described by effective scale-free models where the disorder strength is scaled out. For weak magnetic flux disorder we observe sub-exponential localization at flatband energies in d=1, which differs from the usual Anderson localization. We also find diverging localisation length at flatband energies for weak flux values in d=2. However the character of the eigenstates at these energies is less clear. For weak spin-orbit coupling disorder in d=2 we identify a tunable metal-insulator transition with mobility edges. We also consider the case of mixed spin-orbit and diagonal disorder and obtain the metal-insulator transition driven by the manifold parameter theta.

  1. flat band induced metal-insulator transitions for weak magnetic flux and spin-orbit disorder