Supported bilayerα-borophene(BL-αborophene)on Ag(111)substrate has been synthesized in recent experiments.Based on the experimentally observed quasi-planar C_(6v)B_(36)(1),its monolayer assemblyα^(+)-borophene B_(1...Supported bilayerα-borophene(BL-αborophene)on Ag(111)substrate has been synthesized in recent experiments.Based on the experimentally observed quasi-planar C_(6v)B_(36)(1),its monolayer assemblyα^(+)-borophene B_(11)(P6/mmm)(2),and extensive global minimum searches augmented with density functional theory calculations,we predict herein freestanding BL-α^(+)borophenes B_(22)(Cmmm)(3)and B_(22)(C2/m)(4)which,as the most stable BL borophenes reported to date,are composed of interwoven boron triple chains as boron analogs of monolayer graphene(5)consisting of interwoven carbon single chains.The nearly degenerate eclipsed B_(22)(3)and staggered B_(22)(4)with the hexagonal hole density ofη=1/12 and interlayer bonding density of u=1/4 appear to be two-dimensional semiconductors with the indirect band gaps of 0.952 and 1.144 eV,respectively.Detailed bonding analyses reveal one delocalized 12c-2eπbond over each hexagonal hole in both the B_(22)(3)and B_(22)(4),similar to the situation in monolayer graphene which contains one delocalized 6c-2eπbond over each C_(6)hexagon.Furthermore,these BL-α^(+)borophenes appear to remain highly stable on Ag(111)substrate,presenting the possibility to form supported BL-α+borophenes.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21720102006,21973057,22073048,and 22003034)。
文摘Supported bilayerα-borophene(BL-αborophene)on Ag(111)substrate has been synthesized in recent experiments.Based on the experimentally observed quasi-planar C_(6v)B_(36)(1),its monolayer assemblyα^(+)-borophene B_(11)(P6/mmm)(2),and extensive global minimum searches augmented with density functional theory calculations,we predict herein freestanding BL-α^(+)borophenes B_(22)(Cmmm)(3)and B_(22)(C2/m)(4)which,as the most stable BL borophenes reported to date,are composed of interwoven boron triple chains as boron analogs of monolayer graphene(5)consisting of interwoven carbon single chains.The nearly degenerate eclipsed B_(22)(3)and staggered B_(22)(4)with the hexagonal hole density ofη=1/12 and interlayer bonding density of u=1/4 appear to be two-dimensional semiconductors with the indirect band gaps of 0.952 and 1.144 eV,respectively.Detailed bonding analyses reveal one delocalized 12c-2eπbond over each hexagonal hole in both the B_(22)(3)and B_(22)(4),similar to the situation in monolayer graphene which contains one delocalized 6c-2eπbond over each C_(6)hexagon.Furthermore,these BL-α^(+)borophenes appear to remain highly stable on Ag(111)substrate,presenting the possibility to form supported BL-α+borophenes.
