Thermal And Electronic Transport Properties Of Graphene/Boron Nitride Nanoribbons Heterostructures

Graphene and boron nitride are excellent materials for the nano-electronic devices due to their special structure and excellent properties.Recent theoretical studies showed that the hybridized graphene nanoribbons（GNRs）connected with boron nitride nanoribbons（BNNRs）possess interesting electronic and magnetic properties.Here,we have investigated the spin-dependent transport of zigzag graphene nanoribbon（ZGNRs）and zigzag boron nitride nanoribbon（ZBNNRs）heterojuntion by using the density functional theory calculation combined with the Keldysh nonequilibrium Green’s function approach.This work is divided into two parts:one part is to investigate the thermal spin-dependent transport of Graphene/hexagonal boron nitride vertical heterostructures,and the other part is focused on the electronic transport properties of Graphene/hexagonal boron nitride heterostructure along transport direction connection.First,we study the Graphene/hexagonal boron nitride vertical heterostructures which each edge B atoms are passivated with one H and each edge C atoms are passivated with two H,and is denoted as H₂^CH₁^B（C2）₄（BN）_4.The results showed that the perfect spin seebeck effect and analogy negative differential thermoelectric resistance occur in the device under the temperature difference without gate voltage or bias voltage.An intriguing thermally induced colossal magnetoresistance has been observed,which can be switched between positive and negative value with a temperature control.We also have considered the effects of width on the thermal transport property.The result showed that the gap of device is independent of the width,and the unit number of zigzag graphene nanoribbons and boron nitride nanoribbons can tune the electronic band structure,then modulates the thermal spin transport properties.But devices can still maintain their colossal magnetoresistance and Seebeck effect.When the edge are passivated with two H,the result showed that the AFM configuration presents half-metal property,then has high spin polarization.While FM configuration showed metallic properties,and also has the Seebeck effect but is not perfect,which is high spin polarization.In addition,another structure under study is the heterojunction where the graphene and boron nitride are connected laterally along the transport direction.The results showed that the device has the rectification effect and spin filtering under low bias voltage,and the giant magnetoresistance effect is also found in the device by changing the magnetic direction of the left and right electrodes.Those results suggest that the graphene and hexagonal boron nitride nanoribbon heterostructures would have potential application in the field of spintronics and thermal spintronics.