Research On Magnetoelectric Transport Characteristics Of Nitrogen-doped Two-dimensional Weyl Semimetal WTe₂

The magnetoresistive effect is a phenomenon in which the transport behavior of material carriers under an applied magnetic field varies with the magnitude and direction of the magnetic field,and the magnetoresistive effect has particularly important applications in fields such as magnetic sensor devices and information storage applications.The exploration of materials with magnetoresistive effects has also become a hot issue of interest for modern researchers.With the discovery of graphene materials,two-dimensional materials have steeply come into the limelight.Due to their unique lattice and energy band structures,two-dimensional materials exhibit rich physical phenomena and exotic physical properties,which have aroused extensive research enthusiasm among researchers.In recent years,in the exploration of two-dimensional materials,it has been found that two-dimensional Weyl-erotic semimetallic materials have spontaneous magnetoresistance effect,and it has become a new hot research problem to investigate the source of magnetoresistance effect and how to regulate it.As a typical class II Weyl-semimetal,WTe₂ has not only a layered structure but also many Weyltic electromagnetic transport phenomena,such as unsaturated giant magnetoresistance at low temperature and atmospheric pressure,negative magnetoresistance due to chiral anomalies in Weyl-semimetals,and negative magnetoresistance due to momentum anomalies.The negative magnetoresistive effect of the outer Euclidean semimetallic materials;the Klein tunneling property of the momentum space,etc.The study of these Weyltic magnetoresistance properties is important for the future application of Weyl-semimetallic materials in electronic devices.Therefore,how to regulate the magnetoresistance properties is particularly important for device applications.Among the existing studies,doping,ion implantation,and heterostructure construction are effective means to regulate the physical properties of the materials.In this paper,we investigate the magnetoelectric transport properties of class II Weyl semimetallic WTe₂.The main contents are as follows:（1）A study of the magnetoelectric transport properties of two-dimensional Weyl- semimetallic WTe₂ materials was carried out.The WTe₂ devices with few layers were prepared by micro and nano processing and their magnetoelectric transport properties were tested under low temperature and high magnetic field conditions. The results show that the magnetoresistance effect is observed at low temperature field and the transport characteristics curve also shows semi-metallic characteristics.（2）The modulation of the magnetoelectric transport properties of WTe₂ nanodevices by N doping was investigated.The WTe₂ devices were treated with nitrogen plasma, and the transport measurements and analysis of the WTe₂ devices were performed again,and it was found that their magnetoresistive MR changed significantly before and after nitrogen doping,which was analyzed that the nitrogen atoms had an inhibitory effect on the mobility of electrons and holes in the samples after nitrogen doping,resulting in the change of their magnetoresistive MR.The effect of nitrogen doping on its transport properties is of positive significance for the next application of exalted semimetals in electronic devices.In summary,the results of the study of the magnetoelectric transport properties of WTe₂ show that the transport properties can be modulated by means of doping.The change in internal structure leads to a change in the electron migration mechanism within the material and increases the material resistivity.This has positive implications for further tuning of the magnetoelectric properties and device applications.