The interlayer sliding energy landscape of hexagonal boron nitride (h-BN) is investigated via a van der Waals corrected density functional theory approach. It is found that the main role of the van der Waals forces is to anchor the layers at a fixed distance, whereas the electrostatic forces dictate the optimal stacking mode and the interlayer sliding energy. A nearly free-sliding path is identified, along which band gap modulations of ∼0.6  eV are obtained. We propose a simple geometric model that quantifies the registry matching between the layers and captures the essence of the corrugated h-BN interlayer energy landscape. The simplicity of this phenomenological model opens the way to the modeling of complex layered structures, such as carbon and boron nitride nanotubes.

http://absimage.aps.org/image/MAR11/MWS_MAR11-2010-004484.pdf

Stacking and Registry Effects in Layered Materials: The Case of Hexagonal Boron Nitride

The relative orientation of successive sheets, i.e. the stacking sequence, in layered two-dimensional materials is central to the electronic, thermal, and mechanical properties of the material. Often different stacking sequences have comparable cohesive energy, leading to alternative stable crystal structures. Here we theoretically and experimentally explore different stacking sequences in the van der Waals bonded material hexagonal boron nitride (h-BN). We examine the total energy, electronic bandgap, and dielectric response tensor for five distinct high symmetry stacking sequences for both bulk and bilayer forms of h-BN. Two sequences, the generally assumed AA' sequence and the relatively unknown (for h-BN) AB (Bernal) sequence, are predicted to have comparably low energy. We present a scalable modified chemical vapor deposition method that produces large flakes of virtually pure AB stacked h-BN; this new material complements the generally available AA' stacked h-BN.

Alternative Stacking Sequences in Hexagonal Boron Nitride.

First-principles investigation of the effect of noble metals on the electronic and optical properties of GaN nitride

In this work, we have investigated the adsorption behavior of small gas molecules like CO, NO, CO2, NO2 and NH3 on Yttrium(Y) doped SnS2 monolayer by employing density functional theory simulations. Y-doping effect on the physicochemical properties of the pure SnS 2 monolayer is first studied, then adsorption mechanism was analyzed by adsorption energy, charge transfer, structural properties, magnetic properties , electronic properties such as density of states, charge density and band structure. In addition, the transport properties are evaluated to propound the gas adsorption response of Yttrium (Y) doped -SnS 2 system on the device level. The result shows that all the gas molecules were strongly adsorbed on the Yttrium (Y) site of the Y-doped SnS2 monolayer through formation of strong covalent bonds and Y- doped SnS2 monolayers can be employed as a potential candidate for gas sensing applications. Here in, to evaluate the sensing capability, the molecular model of the adsorption systems was constructed, and density functional theory (DFT) was used to calculate the adsorption behavior of these gases.

Ab-initio modelling for gas sensor device: based on Y-doped SnS2 monolayer

In this work, we have investigated the adsorption behavior of small gas molecules like CO, NO, CO2, NO2 and NH3 on Yttrium(Y) doped SnS2 monolayer by employing density functional theory simulations. Y-doping effect on the physicochemical properties of the pure SnS2 monolayer is first studied, then adsorption mechanism was analyzed by adsorption energy, charge transfer, structural properties, magnetic properties, electronic properties such as density of states, charge density and band structure. In addition, the transport properties are evaluated to propound the gas adsorption response of Yttrium (Y) doped -SnS2 system on the device level. The result shows that all the gas molecules were strongly adsorbed on the Yttrium (Y) site of the Y-doped SnS2 monolayer through formation of strong covalent bonds and Y- doped SnS2 monolayers can be employed as a potential candidate for gas sensing applications. Here in, to evaluate the sensing capability, the molecular model of the adsorption systems was constructed, and density functional theory (DFT) was used to calculate the adsorption behavior of these gases. 

Lalhriatzuala

Papers

Induced magnetic states upon electron–hole injection at B and N sites of hexagonal boron nitride bilayer: A density functional theory study