Magnetic resistance effect of surface nano-structures with spin-split electronic states

为了测量表面纳米结构的磁阻效应，在超高真空（UHV）室中研制了一种四点探头电阻测量系统和电磁体线圈。在对多晶镍箔进行测量的基础上，评价了电阻测量的精度为~0.1μΩ。此外，利用角分辨光电子能谱（ARPES）和自旋分辨光电子能谱（ARPES）研究了吸附Bi和Pb引起的Ge（111）表面超结构的电子结构。在表面态或表面共振带中发现了超过200meV的大自旋分裂。

For the purpose of measuring magnetic resistance effect of surface nano-structures, a 4-point probe resistance measurement system and an electromagnet coil have been developed in an ultra-high vacuum (UHV) chamber. On the basis of the measurement on a polycrystalline Ni foil, the accuracy of the resistance measurement was evaluated to be ～0.1μΩ. Besides, the electronic structures of the surface superstructures on Ge(111) induced by adsorption of Bi and Pb were studied by angle-resolved photoelectron spectroscopy (ARPES) and spin-resolved ARPES. Large spin splittings exceeding 200meV were found for surface-state or surface-resonance bands.