67 巻 (2001) 656 号 p. 632-637
The previous paper on the deformation behavior of the diamond-like carbon (DLC) pointed out the following two things. One is that the content rate of sp3 bonded atom in the initial atomic model was much less than the experimental results. And the other is that the Tersoff type interatomic potential employed in the previous molecular dynamics simulations never resists the torsional deformation. It may be fatal defect when considering the deformation of the amorphous-like imhomogeneous structure. In the present paper, Order (N) tight-binding molecular dynamics scheme (O(N)TB-MD) is applied to elucidate these problems. First, we demonstrate that an environment dependent TB potential proposed by Wang and et al.is applicable to the DLC containing the various crystal structures with different binding energies. Moreover, the density matrix method as an Order (N) scaling is adopted to reduce the drastic computational time with keeping the reasonable accuracy of an interatomic force as the first-order gradient of the potential energy and elastic stiffness as the second-order gradient. It is found that the high content of sp3 in the initial DLC model by quenching process is obtained, which is in good agreement with the experimental results. And the torsional resistance plays an important role in the deformation of the DLC film.