GeTe中铁电极化对自旋霍尔电导的调控研究

利用电场控制电荷的自旋流与电流相互转换是自旋电子器件的关键所在,而这种控制机制在铁电半导体GeTe中可以得到实现,因为其铁电极化可以改变自身的自旋织构。基于密度泛函理论计算,我们发现可以通过铁电极化可以进一步调节自旋霍尔电导(spinHallconductivity,简记为SHC),通过计算得到自旋霍尔电导的一个分量σxyz在带边缘附近可以达到100?/e(?cm)-1的量级,其主要原因在于电极化改变了能带结构。该研究工作为可控的自旋输运的实验和理论研究具有重要的价值,必将推动自旋电子学的进一步发展。

Tunning Spin Hall conductivities in GeTe by Ferroelectric Polarizations

Controlling charge-spin current conversion by electric fields is crucial in spintronic devices,which can be realized in diatom ferroelectric semiconductor GeTe where it is established that ferroelectricity can change the spin texture.The ability of conversion from spin currents to charge currents is only recently demonstrated experimentally.By using the Kubo’s formula,we can evaluate the spin Hall conductivity tensor from the first principles.We demonstrated that the spin Hall conductivity (SHC) can be tuned by ferroelectricity.Through plotting the Rashba parameters and ferroelectricity vs.the ferroelectric displacement,we observed that the origin of SHC σxyz can be attributed to the Rashba effect and the intrinsic spin orbit coupling.The Rashba induced part can be tuned by the electric polarization while that from the intrinsic bulk effect does not show obvious effect.The magnitude of one component of SHC can reach as large as 100 ?/e(?cm)-1 in the vicinity of the band edge,which is promising for engineering spintronic devices.