Transport Properties Of Black Phosphorus Under Magnetic Field

In this paper,the transport properties of black phosphorus under magnetic field are studied theoretically.Our research includes the main transport properties of single-layer,double-layer and superlattice systems under magnetic field and the application of these transport properties in nano-electronic structures.The whole text is divided into the following parts:The first chapter is an introduction,which mainly describes the research background,research methods and some breakthrough research progress of two-dimensional materials and nanodevices in recent years.Particular attention has been paid to graphene and black phosphorus materials which have attracted many researchers'interest in recent years.In this paper,the calculation methods of scattering matrix and transport theory are introduced.In the second chapter,we study the electron transport properties of single-layer black phosphorus under Delta functional magnetic field.Because of the anisotropy of monolayer black phosphorus,the electron tunneling effect depends on the direction under the magnetic field.That is to say,the magnetic transport properties of monolayer black phosphorus in the X and Y directions are different.We have calculated the transmission probability,conductivity and conductivity ratio of single and multiple barriers of black phosphorus in X and Y directions.We find that the transmission probability depends mainly on the incident energy,incident angle and magnetic field strength,whether in the X or Y direction.For a single magnetic barrier,we find that tunneling has a significant momentum filtering effect and depends on the width of the magnetic barrier.For double magnetic barriers,many Fabiy-Perot resonance peaks appear when the distance between two magnetic barriers is not zero,and the distance can adjust the amplitude of the resonance state.In the superlattice system,the cut-off energy of electron transport is not affected by the number of magnetic barriers,that is to say,with the increase of the number of magnetic barriers,the cut-off energy will not change.We also find that the combined effect of magnetic field and electrostatic barrier can aggravate the difference of electron transport between X and Y magnetized structures,resulting in the formation of huge magnetoresistance effects in various magnetic barrier structures.In Chapter 3,we continue to study the electron transport properties of bilayer black phosphorus under Delta functional magnetic field.Similar to single-layer black phosphorus,the transport is mainly affected by incident angle,Fermi energy,magnetic field and electrostatic barrier.The tunneling effect of bilayer black phosphorus in X and Y directions is also direction dependent,and the electron transmission probability in bilayer black phosphorus shows an interesting momentum filtering characteristic in both X and Y directions.For a single magnetic barrier,the momentum filtering characteristics are more obvious,and the effect of barrier width on tunneling is weakened due to the interaction between layers.For double magnetic barriers,the distance L between magnetic barriers also causes the transmission oscillation,but the oscillation amplitude decreases slightly.For the superlattice system,the cut-off energy is slightly different from that of the single-layer black phosphorus system.Because of the interlayer interaction,the cut-off energy and the critical magnetic field intensity change slightly with the change of the magnetic barrier number.Based on the study of transport properties of black phosphorus in.single and double layers under magnetic field,an effective method to control electronic transport and a new scheme to construct electronic devices using black phosphorus materials are theoretically provided.Chapter 4 mainly lists the brief summary of this paper.