Ultrahigh Electron Thermal Conductivity in T-Graphene, Biphenylene, and Net-Graphene

摘要

Although isolated nonhexagonal carbon rings in graphene are associatedwith strain relaxation and curvature, dense and ordered arrangementsof four-, five-, and eight-membered rings with strained carbon–carbonbonds can tile 2D planar layers. Using the Boltzmann transport equationformalism in combination with density functional theory calculations, howthe presence of nonhexagonal rings impacts the thermal conductivity ofthree 2D carbon allotropes: T-graphene (four and eight rings), biphenylene(four, six, and eight rings), and net-graphene (four, six, and eight rings), isinvestigated. The phonon thermal conductivity (κ_(ph)), which captures threephonon,four-phonon, and phonon–electron interactions, is significantlylowered with respect to pristine graphene. In compensation, the electronthermal conductivity (κ_e), which captures electron–phonon interactions,is enhanced to record high values, such that the room-temperature totalthermal conductivity κtotal = κ_(ph) + κ_e approaches the values of pristinegraphene. 2D carbon allotropes could be of interest for applications requiringthermal energy transfer by a combination of diffusion of electrons andphonon vibrations.