Electric field driven quantum phase transition between band insulator and topological insulator

Topological Quantum Phase Transition and 3D Texture Inversion in a Tunable Topological Insulator

The recently discovered three dimensional or bulk topological insulators are expected to exhibit exotic quantum phenomena. It is believed that a trivial insulator can be twisted into a topological state by modulating the spin-orbit interaction or the crystal lattice via odd number of band inversions, driving the system through a topological quantum phase transition. By directly measuring the to...

Switching a normal insulator into a topological insulator via electric field with application to phosphorene.

The study of topological insulators has generally involved search of materials that have this property as an innate quality, distinct from normal insulators. Here we focus on the possibility of converting a normal insulator into a topological one by application of an external electric field that shifts different bands by different energies and induces a specific band inversion, which leads to a...

Temperature-driven transition from a semiconductor to a topological insulator

Electric-field tuning of the surface band structure of topological insulator Sb2Te3 thin films.

We measured the response of the surface state spectrum of epitaxial Sb(2)Te(3) thin films to applied gate electric fields by low temperature scanning tunneling microscopy. The gate dependent shift of the Fermi level and the screening effect from bulk carriers vary as a function of film thickness. We observed a gap opening at the Dirac point for films thinner than four quintuple layers, due to t...

Compensation-driven superconductor-insulator transition

The superconductor-insulator transition in the presence of strong compensation of dopants was recently realized in La doped yttrium barium copper oxide. The compensation of acceptors by donors makes it possible to change independently the concentration of holes n and the total concentration of charged impurities N. We propose a theory of the superconductor-insulator phase diagram in the N ,n pl...