A conventional topological insulator (TI) has gapped bulk states but gapless edge states.
The emergence of the gapless edge states is dictated by the bulk topological invariant of the …

Metasurfaces are subwavelength structured thin films consisting of arrays of units that allow
the control of polarization, phase, and amplitude of light over a subwavelength thickness …

Rapidly growing demands for fast information processing have launched a race for creating
compact and highly efficient optical devices that can reliably transmit signals without losses …

A quadrupole topological insulator, being one higher-order topological insulator with
nontrivial quadrupole quantization, has been intensely investigated very recently. However …

Higher-order topology yields intriguing multidimensional topological phenomena, while
Weyl semimetals have unconventional properties such as chiral anomaly. However, so far …

Topological crystalline insulators (TCIs) can exhibit unusual, quantized electric phenomena
such as fractional electric polarization and boundary-localized fractional charge,,,,–. This …

The conventional bulk-boundary correspondence directly connects the number of
topological edge states in a finite system with the topological invariant in the bulk band …

We demonstrate that multiple higher-order topological transitions can be triggered via the
continuous change of the geometry in kagome photonic crystals composed of three …

Unlike conventional topological materials that carry topological states at their boundaries,
higher‐order topological materials are able to support topological states at boundaries of …

Discovering new topological phases of matter is a major theme in fundamental physics and
materials science. Dirac semimetal provides an exceptional platform for exploring …