Research Of Adjustable Spin-orbit Coupling Effect

With the continuous development of information science,the requirements for electronic devices are converting towards the direction of integration and miniaturization.But the original electronic devices only use the electronic charge attribute,which makes the issue of heating and energy consumption more and more serious during the development process,so Moore's law seems to be approaching the limit.However,the research enthusiasm for further improving the computing power of electronic equipment has not been interrupted.During this period,a subject integrating magnetism,electronics,informatics and other fields,namely spin electronics,has been gradually emerging and received more and more attention.In spintronics,the spin-orbit coupling effect is a very important physical property,so the research of spin-orbit coupling effect becomes the focus of spintronics.In this thesis,the study of spin-orbit coupling effect is mainly divided into two aspects,one is the ferroelectric GeTe,the other is the metal platinum.As we all know,in recent years,a kind of material system called ferroelectric Rashba semiconductor has attracted much attention and GeTe is a representative material in this material system,so the conclusion of the research on the properties of GeTe material can represent the cognition of the whole ferroelectric Rashba semiconductor material system to some extent.In this thesis,we mainly focus on the effect of the external electric field on the spin-orbit coupling and spin Hall conductance.In the process of research,we mainly study the relationship among the external electric field,ferroelectric polarization and spin-orbit coupling effect.In summary,our theoretical calculation shows that the spin texture is closely related to the ferroelectric polarization.When the ferroelectric polarization is reversed,the spin direction is also reversed,which is due to the change of the equivalent coordinate system when the polarization is reversed.We also find that the spin Hall conductance has the contribution of both the intrinsic spin-orbit coupling effect and the Rashba effect,which can be easily controlled by the external electric field.The results show that the electric field can be used to adjust the spin and electron transport properties of ferroelectric Rashba semiconductor,which provides a new thinking dimension for the design of spin electronic devices.Spin Hall effect is a physical phenomenon caused by spin-orbit coupling effect,and spin Hall conductance is an important physical quantity to characterize the spin Hall effect.The research of spin Hall effect in metals is also a focus of researchers in recent years,and Pt is one of the special metals,so this paper also studies Pt.We mainly study the relationship between the deformation of Pt and spin-orbit coupling effect,so we calculate the energy band and spin Hall conductance of Pt under different deformation.It is found that the band structure and the spin Hall conductance of Pt will change under different deformation.The spin Hall conductance will increase with the increase of deformation.We also found that although the deformation has a certain regulatory effect on the spin-orbit coupling effect of Pt,its controllable range is relatively small.