Scattering at magnetic and nonmagnetic impurities on surfaces with strong spin-orbit coupling
Scattering at magnetic and nonmagnetic impurities on surfaces with strong spin-orbit coupling
复制标题
DOI：
10.1103/physrevb.86.195432
复制
发表时间：
2012-11
影响因子：
3.7
通讯作者：
D. Luekermann;S. Sologub;H. Pfnuer;C. Klein;M. H. Hoegen;C. Tegenkamp
中科院分区：
文献类型：
--
作者：
D. Luekermann;S. Sologub;H. Pfnuer;C. Klein;M. H. Hoegen;C. Tegenkamp
用宏观表面磁输运测量方法研究了10 K下Bi、Fe和Co原子在外延Bi（111）膜中的吸附引起的表面态电导率降低。磁输运，直流运输和霍尔数据的详细分析表明，Co和Fe的散射效率是由2比Bi的一个因素更大。而对于后者的电荷转移和费米能级附近的带填充的变化是可以忽略不计的，我们发现，增加了空穴浓度的Co和Fe吸附。这些原子作为受体，每个吸附原子平均吸收约0.5个电子。除了主要的经典磁导信号外，薄膜还显示出弱的反局域化特征，反映了Bi（111）表面态的强自旋轨道耦合。这种行为可以改变为弱本地化的吸附高浓度（0.1单层）的磁性杂质（铁，钴），类似的拓扑绝缘体Bi 2 Se 3上发现的结果。我们的研究结果表明，杂质的化学键形成的细节是至关重要的本地自旋矩和电子散射性质。
Adsorption-induced reduction of surface-state conductivity in epitaxial Bi(111) films, a prototype system with large Rashba-induced surface-state splitting, by adsorbed atoms of Bi, Fe, and Co has been investigated by macroscopic surface magnetotransport measurements at a temperature of 10 K. A detailed analysis of magnetotransport, dc transport, and Hall data reveals that the scattering efficiencies for Co and Fe are larger by a factor of 2 than that for Bi. While for the latter charge transfer and change of band filling near the Fermi level are negligible, we find an increase of hole concentration upon Co and Fe adsorption. These atoms act as acceptors and immobilize on average about 0.5 electrons per adsorbed atom. Besides the dominant classical magnetoconductance signal the films show signatures of weak antilocalization, reflecting the strong spin-orbit coupling in Bi(111) surface states. This behavior can be changed to weak localization by the adsorption of high concentrations (0.1 monolayers) of magnetic impurities (Fe,Co), similarly to results found on the topological insulator Bi2Se3. Our results demonstrate that details of chemical bond formation for impurities are crucial for local spin moments and electronic scattering properties.