New Transfer Methods Of Low-Dimensional Materials And Low Temperature Transport Study Of HfTe₅ Crystal

The discovery of monolayer graphene in 2004 opened the door to the research field of two-dimensional materials.As a new type of material,two-dimensional materials have been widely concerned in many fields such as material properties,topological band properties and so on.Up to now,people have not only limited to the research of a single kind of two-dimensional materials,but pay more attention to the mutual cooperation between various materials,through artificial stacking to form a two-dimensional heterojunction to achieve a variety of application intentions,such as optoelectronic materials,superconducting materials,ferroelectric materials,etc.Based on the topological material HfTe5,this paper introduces various transfer methods for making two-dimensional heterojunctions in recent years,and the idea of automated mass production of various steps in the transfer process.Wish it can be combined with the fiery artificial intelligence field to create an efficient mass production line,laying a solid foundation for the practical application of two-dimensional materials.In addition,various topological properties of HfTe5 with different thicknesses were systematically studied,from bulk materials(micrometers)to thick layers(hundred nanometers)to thin layers(nanometers),and many novel physical properties are discovered.Based on the author's own scientific research experience and understanding,the paper can be divided into the following four parts:(1)Research history of two-dimensional materials,major application progress,and commonly used analytical methods for electrical transport experiments.First,we review the development of two-dimensional materials,summarizes the recent significant progress on two-dimensional materials published in Nature,and understands the background of the subject and the importance of the means of transfer.Subsequently,the common effect in the electric transport experiment-SdH oscillation is introduced.Following the research steps of the physicists pioneers,L.D.Landau,W.J.de Haas,P.M.van Alphen,L.V.Shubnikov,R.E.Peierls,L.Onsager,I.M.Lifshitz,based on the physical principle and the oscillation model,we describe the Lifshitz-Kosevich formula using Fermiology,obtain a series of parameters about oscillation,introduce the method of fitting important physical parameters through oscillation analysis,such as effective mass,Dingle temperature,etc.(2)The reasonable configuration of the laboratory and the flow and methods of the electrical transport experiment.Starting from a series of experimental processes such as sample growth,device preparation,circuit connection,data measurement,and data analysis,the experimental methods and precautions of each step are introduced in detail,and the reasonable construction method of the laboratory is discussed to achieve the highest experiment effectiveness.Subsequently,the various transfer methods and corresponding transfer steps based on different films are carefully summarized,and the concepts and methods of automated mass production based on each step of transfer are proposed to add bricks and tiles to the practical application of two-dimensional heterojunction in the future.(3)Experimental study on low temperature electrical transport of bulk HfTe5 and three-dimensional quantum Hall effect.The approaching three-dimensional quantum Hall effect is found in the bulk samples.Through the analysis of the three-dimensional characteristics,quantization platform,and band characteristics of the sample,we analyze the causes and deficiencies of the three-dimensional quantum Hall effect in HfTe5.(4)Study on the low temperature electrical transport properties of thin layer HfTe5.The samples from 20 nm to 500 nm were prepared and measured by the method of micro-nano processing and transfer.Temperature and magnetic field dependent anisotropic magnetoresistance,negative magnetoresistance and planar Hall effect are found in the samples of tens of nanometers.These novel phenomena and their origins are analyzed in detail.Finally,the previous work is analyzed and summarized,and the future research work is prospected.