Borophane: Stable Two-dimensional Anisotropic Dirac Material with Ultrahigh Fermi Velocity

Borophene (two-dimensional boron sheet) is a new type of two-dimensional material, which was recently grown successfully on single crystal Ag substrates. In this paper, we investigate the electronic structure and bonding characteristics of borophene by first-principle calculations. The band structure of borophene shows highly anisotropic metallic behaviour. The obtained optical properties of borophene exhibit strong anisotropy as well. The combination of high optical transpar...

Two-dimensional (2D) structures of boron atoms so called borophene, have recently attracted remarkable attention. In a latest exciting experimental study, a hydrogenated borophene structure was realized. Motivated by this success, we conducted extensive first-principles calculations to explore the mechanical, thermal conduction, electronic and optical responses of borophene hydride. The mechanical response of borophene hydride was found to be anisotropic in which it can yield...

Hyperbolic materials are receiving significant attention due to their ability to support electromagnetic fields with arbitrarily high momenta and, hence, to achieve very strong light confinement. Here, based on first-principles calculations and many-body perturbation theory, we explore the characteristic of two-dimensional plasmon modes and its hyperbolic properties for two phases of single layer boron hosting tilted Dirac cone, namely, the $hr$-$sB$ and $8Pmmn$ borophene. In...

We have studied the mechanical properties and phonon dispersions of fully hydrogenated borophene (borophane) under strains by first principles calculations. Uniaxial tensile strains along the a- and b-direction, respectively, and biaxial tensile strain have been considered. Our results show that the mechanical properties and phonon stability of borophane are both highly anisotropic. The ultimate tensile strain along the a-direction is only 0.12, but it can be as large as 0.30...

The past decade has witnessed numerous discoveries of two-dimensional (2D) semimetals and insulators, whereas 2D metals are rarely identified. Borophene, a monolayer boron sheet, has recently emerged as a perfect 2D metal with unique structure and electronic properties. Here we study collective excitations in borophene, which exhibit two major plasmon modes with low damping rates extending from infrared to ultraviolet regime. The anisotropic 1D plasmon originates from electro...

First-principles calculations on monolayer 8-{\it Pmmn} borophene are reported to reveal unprecedented electronic properties in a two-dimensional material. Based on a Born effective charge analysis, 8-{\it Pmmn} borophene is the first single-element based monolayered material exhibiting two sublattices with substantial ionic features. The observed Dirac cones are actually formed by the p$_z$ orbitals of one of the inequivalent sublattices composed of uniquely four atoms, yiel...

Superconductivity in two-dimensional compounds is widely concerned, not only due to its application in constructing nano-superconducting devices, but also for the general scientific interests. Very recently, borophene (two-dimensional boron sheet) has been successfully grown on the Ag(111) surface, through direct evaporation of a pure boron source. The experiment unveiled two types of borophene structures, namely $\beta_{12}$ and $\chi_3$. Herein, we employed density-function...

We study the mechanical properties of two-dimensional (2D) boron, borophenes, by first-principles calculations. The recently synthesized borophene with 1/6 concentration of hollow hexagons (HH) is shown to have in-plane modulus C up to 210 N/m and bending stiffness as low as D = 0.39 eV. Thus, its Foppl-von Karman number per unit area, defined as C/D, reaches 568 nm-2, over twofold higher than graphene's value, establishing the borophene as one of the most flexible materials....

We study the electronic transport properties of two-dimensional (2D) fully-hydrogenated borophene (namely, borophane), using the density functional theory and non-equilibrium Green's function approaches. Borophane shows a perfect electrical transport anisotropy and is promising for applications. Along the peak- or equivalently the valley-parallel direction, the 2D borophane exhibits a metallic characteristic and its current-voltage (I-V) curve shows a linear behavior, corresp...

Experimental realization of two-dimensional boron sheets was reported very recently by Feng et. al. using molecular beam epitaxy on silver (111) surface. These boron sheets possess promising electronic and transport properties. We performed the density functional theory (DFT) calculation to see the stability of two $\beta_{12}$ and $\chi$ polymorphs of boron under strain and further studied electronic and transport properties. We verified the directional dependency in electro...