School of Chemistry and Materials Sciences, CAS Key Laboratory of Materials for Energy Conversion, Synergetic Innovation of Quantum Information & Quantum Technology, and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nanoscale. 2019 Nov 7;11(41):19536-19542. doi: 10.1039/c9nr05698j. Epub 2019 Oct 2.
Introducing magnetism in two-dimensional materials is of particular importance for both fundamental research and practical applications in nanoscale spintronics. Herein, we report the lifting of valley degeneracy in a MoS monolayer via magnetic proximity coupling to an insulating antiferromagnetic CrO substrate and the gate-voltage tunability of the MoS/CrO heterojunction on the basis of first-principles calculations. Our calculations suggest that there is a large Zeeman splitting of 23.4 meV in the MoS monolayer due to strong spin-orbit coupling, corresponding to a magnetic exchange field of 100 T. Both spin and valley indices flip when the magnetic ordering of CrO is reversed. More interestingly, the charge transfer, magnetic moment, band gap and Schottky barrier of the heterojunction can be tuned continually by applying an external out-of-plane gate voltage, resulting in variable valley Zeeman splitting ranging from 11.3 to 34.5 meV. These findings demonstrate great potential applications of the CrO/MoS heterojunction in nanoscale spintronics.
将磁性引入二维材料对于纳米尺度自旋电子学的基础研究和实际应用都具有特别重要的意义。在此，我们通过第一性原理计算报告了通过磁近邻耦合到绝缘反铁磁 CrO 衬底将 MoS 单层中的谷简并消除，以及基于此的 MoS/CrO 异质结的栅极电压可调性。我们的计算表明，由于强自旋轨道耦合，MoS 单层中有一个 23.4 meV 的大塞曼分裂，对应于 100 T 的磁交换场。当 CrO 的磁序反转时，自旋和谷指数都会翻转。更有趣的是，通过施加外部面外栅极电压可以连续调节异质结的电荷转移、磁矩、能带隙和肖特基势垒，从而导致谷塞曼分裂从 11.3 到 34.5 meV 的变化。这些发现表明 CrO/MoS 异质结在纳米尺度自旋电子学中有很大的应用潜力。
