Topological valley transport of spoof surface acoustic waves.

In recent years, topological physics has attracted broad attention in condensed matter systems. Here, we report an experimental study on topological valley transport of spoof surface acoustic waves (SAWs). Specifically, we realize valley pseudospins and a valley Hall phase transition by tuning the structural size of adjacent grooves. In addition to a direct visualization of the vortex chirality-locked beam splitting for the bulk valley states, valley-projected edge states are observed in straight and bent interface channels formed by two topologically distinct valley Hall insulating phases. The experimental data agree well with our numerical predictions. The topological transport of spoof SAWs, encoded with valley information, provides more possibilities in design novel acoustic devices based on the valley-contrasting physics. [ABSTRACT FROM AUTHOR]