Modeling the Si(100) Surface

H2 Induced Unbuckling

      The Si[100] surface is the Si surface most frequently used for building electronic devices. An experimental study observed that when a bare Si[100] surface is exposed to H₂ at low temperatures, H₂ molecules tend to chemisorb next to each other.¹ This effect can potentially be used to build long linear nanostructures on the Si[100] surface. They could serve as a bridge between conventional electronic devices and molecular electronics.

      I modeled the adsorption of H2 on the Si[100] surface using a plane-wave code VASP at the PW91 level of theory and found that the chemisorption of H2 molecules in orderly rows is indeed more favorable than in random order.

      I also modeled H₂-induced changes in Si[100] surface topology using VASP at the PW91 level of theory and the GAMESS package at the MRMP2 level of theory.

¹Dürr, M.; Hu, Z.; Biedermann, A.; Höfer, U.; Heinz, T.F. Phys. Rev. Lett. 2002, 88, 046104.