Observation of acoustic hybrid topological phases induced by the p-d orbital interactions

In spinless systems, growing attention has recently been attracted to synthetic gauge fields, which redefine the fundamental crystal symmetries by utilizing the projective algebraic relation. Hitherto, synthetic gauge fields have been commonly investigated in single orbital systems, and explorations on hybrid orbitals remain elusive in acoustics. Here, we report the experimental observation of hybrid topological phases induced by hybrid synthetic gauge flux, which is formed by the interaction between p and d orbitals embedded in acoustic cavities. By breaking the translation symmetries of L_x and/or L_y, we unambiguously demonstrate the first-order Möbius edge states and higher-order corner states. This work establishes a platform for seeking exotic topological phases induced by hybrid-orbitals interactions and initializing the framework of hybrid-orbitals-related topological physics. Potential applications can be anticipated in scenarios such as high-quality sensing and robust wave trapping due to the stepwise energy distribution of the hybrid topological phase.