Details

Autor(en) / Beteiligte

• Ahn, Jeonghwan
• Lee, Hoonkyung
• Kwon, Yongkyung

Titel

Prediction of stable C sub(7/12) and metastable C sub(4/7) commensurate solid phases for super(4)He on graphite

Ist Teil von

• Physical review. B, 2016-02, Vol.93 (6)

Erscheinungsjahr

2016

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• Using a substrate potential described by a pairwise sum of empirical super(4)He-C interatomic potentials, we have performed path-integral Monte Carlo calculations for super(4)He adatoms on graphite. It is found that a second-layer commensurate structure is not stable above an incommensurate first-layer triangular solid. This is consistent with the conclusion of the previous theoretical study of Corboz et al.[Phys. Rev. B 78, 245414 (2008)] that was based on a laterally averaged one-dimensional potential. On the other hand, we observe a new stable C sub(7/12) commensurate solid in the first super(4) He layer at the areal density of 0.111 A super(-2), which is close to the second-layer promotion density. This high-density commensurate solid exhibits a [radical]12 x [radical]12 structure registered to the graphite surface that is not disrupted by the development of the second super(4)He layer. Furthermore, a second-layer 4/7 commensurate structure relative to the first-layer C sub(7/12) solid is found to be at least metastable, opening the possibility of two-dimensional supersolidity.