Possible domain-type collective dimerization of graphite induced by interlayer charge transfer excitations in the visible region

We theoretically study possible domain-type collective dimerizations of graphite induced by interlayer charge transfer excitations in the visible region. Using the semiempirical Brenner's model, we have calculated the adiabatic energy along the path that starts from original two distant graphite layers and finally reaches the dimerized domain which consists of about 100 carbons with interlayer sigma bonds. The energy barrier between this new domain and the starting graphite is shown to be on the order of 1 eV, being easily overcome by applying a few visible photons. The early stage dynamics is also studied in the model that a photogenerated electron-hole pair spanning two layers, locally contracts the interlayer distance through the Coulomb attraction, and results in the sigma-bond formation. Our considerations are aimed at clarifying mechanisms of interlayer dimerization recently observed experimentally.