• Chiral valley phonons and flat phonon bands in moiré materials

    An object is chiral if it is distinguishable from its mirror image, for example, one's left and right hands. Chirality, or handedness, has played a vital role in understanding many phenomena in physics, chemistry, and biology. In this work, we theoretically demonstrated that the collective vibrations of atoms, or phonons, in a two-dimensional moiré material can be chiral.