Weyl semimetals are topological materials whose low-energy excitations obey the Weyl equation. In a Weyl semimetal, the conduction and valence bands touch at discrete points in momentum space called ...
Excitons, a bound state of an electron and an electron hole, can form when a given material absorbs a photon above its bandgap energy. The photon excites an electron from the valence band into the ...