Related Experiment Video
Updated: Jun 3, 2026
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
Topological phase transition and texture inversion in a tunable topological insulator
1Joseph Henry Laboratory of Physics, Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Science (New York, N.Y.)
|April 2, 2011
Summary
Researchers observed a topological quantum phase transition in a tunable spin-orbit system, BiTl(S(1-δ)Se(δ))(2). This transition visualizes topological state formation and may explain fractional topological phenomena.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Phenomena
Background:
- Three-dimensional topological insulators are predicted to exhibit exotic quantum phenomena.
- Trivial insulators can transition to topological states by tuning spin-orbit interaction or crystal lattice.
- Topological quantum phase transitions are key to understanding these exotic states.
Purpose of the Study:
- To directly measure topological quantum numbers and invariants in a tunable system.
- To observe and visualize the formation of a topological state.
- To investigate the physical basis for fractional topological phenomena.
Main Methods:
- Direct measurement of topological quantum numbers and invariants.
- Utilized a tunable spin-orbit system: BiTl(S(1-δ)Se(δ))(2).
- Observed vortex-like polarization states and 3D vectorial textures.
Main Results:
- Successfully observed a topological quantum phase transition in BiTl(S(1-δ)Se(δ))(2).
- Visualized the formation of the topological state.
- Observed a chirality transition in spin momentum-locked surface electrons and texture inversion.
Conclusions:
- The observed phase transition and texture inversion provide a physical basis for fractional topological phenomena, such as fractional charge (±e/2).
- The study demonstrates a method for visualizing topological state formation in tunable materials.
- This work advances the understanding of quantum phase transitions in topological insulators.
Related Concept Videos
01:21Phase Transitions
A phase transition is the process in which a substance changes from one state of matter to another, like from a solid to a liquid, liquid to gas, or vice versa, at a specific temperature and under given pressure conditions. This change is spontaneous and is affected by alterations in temperature and pressure. These parameters impact the strength of the forces between molecules (intermolecular forces) in the substance.During a phase transition, both the initial and final phases of the substance...
02:31Phase Transitions
Whether solid, liquid, or gas, a substance's state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the solid pack closely together, generally in a pattern. The particles vibrate about their fixed positions but do not move or squeeze past their neighbors. In liquids, although the particles are closely spaced, they are randomly arranged. The position of the particles are not fixed—that is, they are free to move past their neighbors to occupy...
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
01:19Phase Diagram
The phase of a given substance depends on the pressure and temperature. Thus, plots of pressure versus temperature showing the phase in each region provide considerable insights into the thermal properties of substances. Such plots are known as phase diagrams. For instance, in the phase diagram for water (Figure 1), the solid curve boundaries between the phases indicate phase transitions (i.e., temperatures and pressures at which the phases coexist).
01:24Phase Diagram
A phase diagram is a graphical representation of the physical states of a substance under different conditions of temperature and pressure. It shows the boundaries between solid, liquid, and gas phases and the conditions at which these phases coexist in equilibrium. An area in a phase diagram represents a single phase, whereas lines or phase boundaries represent the equilibrium between two phases.In the phase diagram of water, the boundary line between the solid and liquid states illustrates...
02:33Phase Transitions: Sublimation and Deposition
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...