Topological acoustics is an emerging field that lies at the intersection of condensed matter
physics, mechanical structural design and acoustics engineering. It explores the design and …

Light and sound are the most ubiquitous forms of waves, associated with a variety of
phenomena and physical effects such as rainbows and echoes. Light and sound, both …

The topological properties of an object, associated with an integer called the topological
invariant, are global features that cannot change continuously but only through abrupt …

The concept of topological energy bands and their manifestations have been demonstrated
in condensed matter systems as a fantastic paradigm toward unprecedented physical …

Besides chiral edge states, the hallmark of quantum Hall insulators, antichiral edge states
can exhibit unidirectional transport behavior but in topological semimetals. Although such …

Dirac semimetals, the materials featuring fourfold degenerate Dirac points, are critical states
of topologically distinct phases. Such gapless topological states have been accomplished by …

Nodal links are special configurations of band degeneracies in the momentum space, where
nodal line branches encircle each other. In PT symmetric systems, nodal lines can be …

The past decade has seen a proliferation of topological materials for both insulators and
semimetals in electronic systems and classical waves. Topological semimetals exhibit …

Three-dimensional topological semimetals have attracted tremendous attention across
multiple disciplines. Recently, a novel class of nodal-line semimetals hosting fourfold nodal …

A four-fold-degenerate three-dimensional (3D) Dirac point, represents a degenerate pair of
Weyl points carrying opposite chiralities. Moreover, 3D Dirac crystals have shown many …