Polarons in two-dimensional atomic crystals

Polarons are quasiparticles that emerge from the interaction of fermionic particles with bosonic fields1. In crystalline solids, polarons form when electrons and holes become dressed by lattice vibrations. While experimental signatures of polarons in bulk three-dimensional materials abound4–14, only rarely have polarons been observed in two-dimensional atomic crystals. Here, we shed light on this asymmetry by developing a quantitative ab initio theory of polarons in atomically thin crystals. Using this conceptual framework, we determine the real-space structure of the recently observed hole polaron in hexagonal boron nitride, discover a critical condition for the existence of polarons in two-dimensional crystals and establish the key materials descriptors and the universal laws that underpin polaron physics in two dimensions. When electrons in a crystal interact with the surrounding lattice, they can form quasiparticles known as polarons. A computational approach to studying polarons in two-dimensional materials explains why they are rarely observed in these systems.