Rashba coupling amplification by a staggered crystal field.
Rashba coupling amplification by a staggered crystal field.
复制标题
DOI：
10.1038/ncomms11258
复制
发表时间：
2016-04-19
影响因子：
16.6
通讯作者：
Gauzzi A
中科院分区：
文献类型：
--
作者：
Santos-Cottin D;Casula M;Lantz G;Klein Y;Petaccia L;Le Fèvre P;Bertran F;Papalazarou E;Marsi M;Gauzzi A
相对论效应诱导非平凡电子态的材料在自旋电子学应用中有着广泛的应用前景。一个例子是分裂的带与相反的自旋手性产生的Rashba自旋轨道耦合在不对称的潜力。迄今为止，已经获得了相当大的分裂使用重元素，其中这种耦合是固有的强，或大的表面电场。在这里，通过角分辨光电子能谱和第一性原理计算，我们给出了一个大的Rashba耦合的0.25 eV的电子伏特的证据，导致一个显着的带分裂高达0.15 eV的隐藏的自旋手性极化中心对称BaNiS 2。这可以用一个巨大的1.4 V <$−1的交错晶场来解释，它是由滑动面对称性产生的，在Ni位置打破了反转对称性。在不存在重元素的情况下，这个意想不到的结果证明了Rashba耦合放大的有效机制，可以促进自旋轨道能带工程。 未来的自旋电子器件可能会利用自旋轨道相互作用，这种相互作用通常来自对称性的破坏，并强烈影响电子行为。在这里，作者证明了放大Rashba耦合的晶体场，打破了局部反转对称性在镍网站BaNiS 2。
There has been increasing interest in materials where relativistic effects induce non-trivial electronic states with promise for spintronics applications. One example is the splitting of bands with opposite spin chirality produced by the Rashba spin-orbit coupling in asymmetric potentials. Sizable splittings have been hitherto obtained using either heavy elements, where this coupling is intrinsically strong, or large surface electric fields. Here by means of angular resolved photoemission spectroscopy and first-principles calculations, we give evidence of a large Rashba coupling of 0.25 eV Å, leading to a remarkable band splitting up to 0.15 eV with hidden spin-chiral polarization in centrosymmetric BaNiS2. This is explained by a huge staggered crystal field of 1.4 V Å−1, produced by a gliding plane symmetry, that breaks inversion symmetry at the Ni site. This unexpected result in the absence of heavy elements demonstrates an effective mechanism of Rashba coupling amplification that may foster spin-orbit band engineering. Future spintronic devices may exploit spin-orbit interactions, which often emerge from broken symmetries and strongly influence electronic behaviour. Here, the authors evidence the amplification of Rashba coupling by a crystal field that breaks the local inversion symmetry at the Ni site in BaNiS2.