title: Topological phase transition and texture inversion in a tunable topological insulator.
abstract: 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, driving the system through a topological quantum phase transition. By directly measuring the topological quantum numbers and invariants, we report the observation of a phase transition in a tunable spin-orbit system, BiTl(S(1-δ)Se(δ))(2), in which the topological state formation is visualized. In the topological state, vortex-like polarization states are observed to exhibit three-dimensional vectorial textures, which collectively feature a chirality transition as the spin momentum-locked electrons on the surface go through the zero carrier density point. Such phase transition and texture inversion can be the physical basis for observing fractional charge (±e/2) and other fractional topological phenomena.
authors: Joseph Henry Laboratory of Physics, Department of Physics, Princeton University, Princeton, NJ 08544, USA.
authors: Su-Yang
authors: SY
authors: Xu
authors: Y
authors: Y
authors: Xia
authors: L A
authors: LA
authors: Wray
authors: S
authors: S
authors: Jia
authors: F
authors: F
authors: Meier
authors: J H
authors: JH
authors: Dil
authors: J
authors: J
authors: Osterwalder
authors: B
authors: B
authors: Slomski
authors: A
authors: A
authors: Bansil
authors: H
authors: H
authors: Lin
authors: R J
authors: RJ
authors: Cava
authors: M Z
authors: MZ
authors: Hasan