Related Experiment Video
Updated: Jan 10, 2026
09:00
Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
10.4K
Higher-order topological point states ofe/2 charge
Xiaoyin Li1, Jia-Xin Zhong2, Yiwei Peng3,4,5,6
1Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112, United States of America.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|November 28, 2025
Summary
Researchers introduce higher-order topological point states (HOTPS) in inner vacancies of 2D materials. These states mimic corner states but offer greater control and novel applications in topological physics.
Area of Science:
- Condensed Matter Physics
- Metamaterials Science
- Topological Physics
Background:
- Two-dimensional higher-order topological insulators (HOTIs) exhibit unique topological corner states.
- These corner states are crucial for manipulating particles but are limited by their fixed positions on the sample boundary.
Purpose of the Study:
- To propose and experimentally realize a new type of topological state, higher-order topological point states (HOTPS), located at inner vacancies.
- To overcome the limitations of boundary-localized corner states in higher-order topological insulators.
Main Methods:
- Theoretical proposal of HOTPS in two-dimensional HOTIs with inner vacancies.
- Experimental realization of HOTPS in acoustic and photonic metamaterials based on a Kekulé lattice.
- Investigation of inter-state interactions by varying the distance between vacancies.
Main Results:
- HOTPS were successfully realized at zero-dimensional inner vacancies, carrying a fractional charge of e/2.
- The experimental results confirmed the existence of in-gap HOTPS and their energy splitting.
- Observed topology-modified longer-range interactions between HOTPS.
Conclusions:
- Inner vacancies in 2D HOTIs can host topological states with properties analogous to boundary corner states.
- HOTPS offer more controllable positioning and novel topological phenomena, expanding the scope of higher-order topological insulator research.
- This work paves the way for new applications utilizing topological states in engineered materials.
Related Concept Videos
01:12Electric Potential Energy of Two Point Charges
6.9K
The electric potential energy of a test charge in a uniform eclectic field can be generalized to any electric field produced by static charge distribution. Consider a positive test charge in an electric field produced by another static positive charge. If the test charge is moved away from the static charge, then the electric field does the positive work on the test charge, and the electric potential energy of the test charge decreases as it moves away from the static charge. Here the electric...
6.9K
01:25Electric Field Lines
9.1K
The three-dimensional representation of the electric field of a positive point charge requires tracing the electric field vectors, whose lengths decrease as the square of their distance from the charge and which point away from the charge at each point. This vector field is no doubt challenging to visualize. The visualization of electric fields becomes quickly intractable as the number of charges increases.
The solution to this problem is to use electric field lines, which are not vectors but...
The solution to this problem is to use electric field lines, which are not vectors but...
9.1K
01:17Continuous Charge Distributions
7.9K
Imagine a bucket of water. It contains many molecules, of the order of 1026 molecules. Thus, although it contains discrete elements (molecules) at the microscopic level, macroscopically, it can be considered continuous. Small volume elements of water, infinitesimal compared to the bulk of the bucket's volume, still contain many molecules. Under this framework, quantized matter is approximated as continuous for practical purposes.
The electric charge can also be subjected to an analogical...
The electric charge can also be subjected to an analogical...
7.9K
01:16Second Uniqueness Theorem
2.6K
Consider a region consisting of several individual conductors with a definite charge density in the region between these conductors. The second uniqueness theorem states that if the total charge on each conductor and the charge density in the in-between region are known, then the electric field can be uniquely determined.
In contrast, consider that the electric field is non-unique and apply Gauss's law in divergence form in the region between the conductors and the integral form to the surface...
In contrast, consider that the electric field is non-unique and apply Gauss's law in divergence form in the region between the conductors and the integral form to the surface...
2.6K
01:21Energy Associated With a Charge Distribution
1.9K
The work done to bring a charge through a distance r is given by the potential difference between the initial and the final position. To assemble a collection of point charges, the total work done can be expressed in terms of the product of each pair of charges divided by their separation distance, defined with respect to a suitable origin. Solving this expression gives the energy stored in a point charge distribution.
1.9K
01:23Electric Field of a Charged Disk
3.0K
The simplest case of a surface charge distribution is the uniformly charged disk. Calculating its electric field also helps us calculate the electric field of a large plane of charge.
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
3.0K