Shikin A M, Rybkina A A, Estyunin D A, Klimovskikh I I, Rybkin A G, Filnov S O, Koroleva A V, Shevchenko E V, Likholetova M V, Voroshnin V Yu, Petukhov A E, Kokh K A, Tereshchenko O E, Petaccia L, Di Santo G, Kumar S, Kimura A, Skirdkov P N, Zvezdin K A, Zvezdin A K
Saint Petersburg State University, Saint Petersburg, 198504, Russia.
Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, 12489, Berlin, Germany.
Sci Rep. 2021 Dec 2;11(1):23332. doi: 10.1038/s41598-021-02493-8.
Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.
掺杂磁性元素的极性 Rashba 型半导体 BiTeI，由于其强自旋 - 轨道耦合和内部铁磁有序性的结合，构成了自旋电子学和量子计算未来发展最有前景的平台之一。后者源于磁性杂质，能够在 Rashba 能带的克莱默斯点（KP 能隙）处打开一个能隙。在当前使用角分辨光电子能谱（ARPES）的工作中，我们表明，在 V 掺杂的 BiTeI 情况下，KP 能隙非单调地依赖于掺杂水平。我们观察到，能隙随着 V 浓度的增加而增大，直到达到 3%，然后开始减小。此外，我们发现，通过超导量子干涉器件（SQUID）磁力计研究的施加磁场下样品的饱和磁化强度与掺杂水平具有相似的行为。理论分析表明，这种非单调行为可以通过在一定掺杂水平以上磁性杂质的反铁磁耦合原子的增加来解释。这导致畴中总磁矩的减小，从而如实验中所观察到的那样导致 KP 能隙的减小。这些发现为磁性掺杂 Rashba 型半导体中内部磁有序的产生以及随之而来的 KP 能隙的打开提供了进一步的见解。
