Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Topological insulators are materials that are insulating in their interior but can support the flow of electrons on their surface. The underlying cause is time-reversal symmetry: their physics is independent of whether time is flowing backward or forward. These surface states are robust, maintained even in the presence of surface defects.
The superconducting proximity effect has not been experimentally demonstrated in a quantum anomalous Hall insulator. Now this effect is observed in the chiral edge state of a ferromagnetic topological insulator.
In photonic crystal systems, topologically protected edge states and corner states can be achieved by breaking spatial inversion symmetry. The authors propose a broadband valley photonic crystal with a relative bandwidth up to 59.65%, demonstrating ultrabroadband topological transmission and two types of corner states with valley switch ability and selectivity.
The interplay between topology and fractals in real materials has remained challenging to study. Now, topological states are demonstrated in fractional-dimensional Sierpinski triangles made from bismuth.
Topological pump offers a new perspective on the construction and application of topological states. Based on higher-order topological corner pump, the authors demonstrate some interesting transport phenomena (e.g., topological splitting effect) in a 3D modulated phononic crystal with arbitrarily controllable pumping paths.
The observation of edge modes in topological systems is challenging because precise control over the sample and occupied states is required. An experiment with atoms in a driven lattice now shows how edge modes with programmable potentials can be realized.
In solids, the quantum metric captures the quantum coherence of the electron wavefunctions. Recent experiments demonstrate the detection and manipulation of the quantum metric in a noncollinear topological antiferromagnet at room temperature.
The quantum anomalous Hall effect holds promise for quantum resistance metrology, but has been limited to low operating currents. A measurement scheme that increases the effect’s operational current is now demonstrated — a scheme that could also be used more generally to improve the performance of existing primary quantum standards of resistance based on the conventional quantum Hall effect.
An all-electric switch of the persistent electron swirl in a quantum anomalous Hall state enables researchers to flip the electronic chirality of this quantum state.
Understanding lattice-geometry-driven electronic structure and orbital character in a titanium-based superconducting kagome metal provides insights into the non-trivial topology and electronic nematicity of correlated quantum matter.