title: Cohesion energetics of carbon allotropes: quantum Monte Carlo study.
abstract: We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp(3)-bonded diamond, sp(2)-bonded graphene, sp-sp(2) hybridized graphynes, and sp-bonded carbyne. The computed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values determined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases systematically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of γ-graphyne, the most energetically stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experimental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally, we conclude that the cohesive energy of a newly proposed graphyne can be accurately estimated with the carbon-carbon bond energies determined from the cohesive energies of graphene and three different graphynes considered here.
authors.affiliation: Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Hyeondeok
authors.initials: H
authors.lastname: Shin
authors.affiliation: Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Sinabro
authors.initials: S
authors.lastname: Kang
authors.affiliation: Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Jahyun
authors.initials: J
authors.lastname: Koo
authors.affiliation: Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Hoonkyung
authors.initials: H
authors.lastname: Lee
authors.affiliation: Materials Science and Technology Division and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: Jeongnim
authors.initials: J
authors.lastname: Kim
authors.affiliation: Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701, South Korea.
authors.forename: Yongkyung
authors.initials: Y
authors.lastname: Kwon