EN
A novel sp^3-bonded nanosize domain, known as a diaphite which is an intermediate state between a graphite and a diamond, is generated by the irradiation of visible laser pulse onto a graphite crystal. The sp^3 structure is well stabilized by shear displacement between neighboring graphite layers. We theoretically study the interlayer sp^3 bond formation with frozen shear displacement in a graphite crystal, using a classical molecular dynamics and a semi-empirical Brenner potential. We show that a pulse excitation under the fluctuation of shearing motion of carbons in an initial state can generate interlayer sp^3 bonds which freeze the shear, though no frozen shear appears if there is no fluctuation initially. Moreover, we investigate a pulse excitation under the coherent shearing motion and consequently obtain that the sp^3-bonded domain with frozen shear is efficiently formed. We conclude that the initial shear is important for the photoinduced sp^3 nanosize domain formation.