Dear Colleagues!
Usually the exciton binding energy of a material is given in form of a number (~40 meV) but the temperature dependence is either not strong or not usually studied. In term of band-gap vs. temperature there is, for example, extensive theoretical description.
Is someone aware of similar theory on exciton binding energy vs. temperature? only "discontinuous models" which usually attribute the change to a phase change of the material, seem common.
Yours,
Chris
Dear Martin!
Thank you for your answer. Indeed I considered both but the temperature dependence of either terms would not satisfy the apparent drop of binding energy. I further consider that I do not observe the dynamics of excitons but rather polarons, which might couple strongly with the lattice (the energy of the binding-energy decay is of the magnitude of phonon energies ~30 meV), which, in turn, is very close to the exciton binding energy itself.
Since all effects are so close in energy I find it hard to find any clue as to "which energy is which".
The exciton-phonon coupling may modify the exciton binding energy to a certain extent. Article Influence of exciton-phonons coupling on the exciton binding...