Tuning Electronic and Structural Properties of Triple Layers of Intercalated Graphene and Hexagonal Boron Nitride: An Ab
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Tuning Electronic and Structural Properties of Triple Layers of Intercalated Graphene and Hexagonal Boron Nitride: An Ab-initio Study. Samir S. Coutinho1, David L. Azevedo2,3 and Douglas S. Galvão1 1 Instituto de “Física Gleb Wataghin”, Universidade Estadual de Campinas, CEP 13082-70, Campinas - SP, Brazil. 2 Departamento de Física, Universidade Federal do Maranhão, CEP 65080-580, São Luís - MA Brazil. 3 Departamento de Física, Universidade Federal do Rio Grande do Norte, CEP 59072-970, Natal – RN, Brazil. ABSTRACT Recently, several experiments and theoretical studies demonstrated the possibility of tuning or modulating band gap values of nanostructures composed of bi-layer graphene, bi-layer hexagonal boron-nitride (BN) and hetero-layer combinations. These triple layers systems present several possibilities of stacking. In this work we report an ab initio (within the formalism of density functional theory (DFT)) study of structural and electronic properties of some of these stacked configurations. We observe that an applied external electric field can alter the electronic and structural properties of these systems. With the same value of the applied electric field the band gap values can be increased or decreased, depending on the layer stacking sequences. Strong geometrical deformations were observed. These results show that the application of an external electric field perpendicular to the stacked layers can effectively be used to modulate their inter-layer distances and/or their band gap values. INTRODUCTION In the last years a large number of experimental and theoretical studies on graphene systems, including monolayers and bilayers, were published. This is due in part to their exceptional electronic and mechanical proprieties [1-4]. Due to its unique structural properties (just one-atom thick layer) and high mobility charge carriers at room temperature, graphene has a high potential application in a series of new nanodevices [1,2,5,6]. Its inorganic equivalent, hexagonal-Boron Nitride (h-BN) monolayer, has also been recently obtained [7,8]. Although most studies up to now has been focused on single layers (graphenes), more recently there is a great interest in studying few-layers (mainly double and triple layers). These systems are very attractive structures to be investigated. One possible application, for instance, it is to use an applied external electric field to modulate their band gap values [9-11]. The graphene zero-gap is one the main limitations to its use in transistors. However, graphene and BN few-layer systems seem to present opposite behavior with relation to band gap value changes as a function of an applied external electric field perpendicular to the layers [11-16]. While for graphene bilayers the band gap value increases (up a limit) as a function of the increasing of the electric field value, for BN it decreases. One natural question is what will be the band gap value behavior for heterosystems composed of graphene and BN layers. The study of these aspects is one of the objectives of the pre
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