Topological Phase Transition and 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, driving the system through a top...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2011-04, Vol.332 (6029), p.560-564
Main Authors: Xu, Su-Yang, Xia, Y., Wray, L. A., Jia, S., Meier, F., Dil, J. H., Osterwalder, J., Slomski, B., Bansil, A., Lin, H., Cava, R. J., Hasan, M. Z.
Format: Article
Language:English
Subjects:
Binding energy
Carrier density
Chirality
Clean metal, semiconductor, and insulator surfaces
Condensed matter: electronic structure, electrical, magnetic, and optical properties
Electron and ion emission by liquids and solids
impact phenomena
Electron density of states and band structure of crystalline solids
Electron states
Elementary excitations
Exact sciences and technology
Fermi surface: calculations and measurements
effective mass, g factor
Fermi surfaces
Insulators
Invariants
Inversions
Materials
Mathematical surfaces
Mathematical triviality
Other inorganic compounds
Phase transformations
Photoemission and photoelectron spectra
Physics
Surface layer
Surface texture
Texture
Topological vector spaces
Topology
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Summary: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(S₁— 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.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1201607