Pentagonal monolayer crystals of carbon, boron nitride, and silver azide

Abstract

In this study, we present a theoretical investigation of structural, electronic, and mechanical properties of pentagonal monolayers of carbon (p-graphene), boron nitride (p-B2N4 and p-B4N2), and silver azide (p-AgN3) by performing state-of-the-art first principles calculations. Our total energy calculations suggest feasible formation of monolayer crystal structures composed entirely of pentagons. In addition, electronic band dispersion calculations indicate that while p-graphene and p-AgN3 are semiconductors with indirect bandgaps, p-BN structures display metallic behavior. We also investigate the mechanical properties (in-plane stiffness and the Poisson's ratio) of four different pentagonal structures under uniaxial strain. p-graphene is found to have the highest stiffness value and the corresponding Poisson's ratio is found to be negative. Similarly, p-B2N4 and p-B4N2 have negative Poisson's ratio values. On the other hand, the p-AgN3 has a large and positive Poisson's ratio. In dynamical stability tests based on calculated phonon spectra of these pentagonal monolayers, we find that only p-graphene and p-B2N4 are stable, but p-AgN3 and p-B4N2 are vulnerable against vibrational excitations.Flemish Science Foundation (FWO-Vl); Methusalem foundation of the Flemish government; FWO Pegasus Long Marie Curie Fellowship; TUBITAK (114F397

Penta-BxNy sheet: a density functional theory study of two-dimensional material

“…For the hydroxyl group adsorbed penta -BN 2 , each hydroxyl group could bind one electron of each dinitrogen in the covalent-like bond, which could also make the metal-semiconductor transition. Here, we would like also to mention Yagmurcukardes et al .’s studies of pentagonal B 2 N 4 and B 4 N 2 on the bandstructures and mechanical properties (for example, the stiffness) 47 . In comparison, we have investigated all the possible pentagonal monolayer structure candidates by changing composition species in the primitive unit cell.…”

Anisotropic Phonon Response of Few‐Layer PdSe2 under Uniaxial Strain

“…Anisotropic 2D layered materials such as black phosphorus, [ 1,2 ] ReS 2 , [ 3,4 ] and many other candidates [ 5–11 ] show directionally dependent physical properties such as mechanical flexibility, [ 12,13 ] thermal conductivity, [ 14–17 ] and optical responsivity. [ 18–20 ] Pentagonal PdSe 2 , a transition metal dichalcogenide (TMDC), has recently joined this 2D family.…”

Contact properties of a vdW heterostructure composed of penta-graphene and penta-BN2 sheets

“…The unique geometry and novel properties of PG have stimulated a lot of study in the field of 2D materials, leading to the discovery of a new class of 2D materials entirely composed of pentagonal structural units explored theoretically [11][12][13][14][15][16][17][18][19][20][21][22][23][24] and experimentally. 25,26 On the other hand, it has been demonstrated that 2D materials can be used to construct van der Waals (vdW) heterostructures for electronic devices.…”