Electrical manipulation of the valley degree of freedom in transition metal dichalcogenides is central to developing valleytronics. Towards this end, ferromagnetic contacts, such as Ga(Mn)As and permalloy, have been exploited to inject spin-polarized carriers into transition metal dichalcogenides to realize valley-dependent polarization. However, these materials require either a high external magnetic field or complicated epitaxial growth steps, limiting their practical applications. Here we report van der Waals heterostructures based on a monolayer WSe₂ and an Fe₃GeTe₂/hexagonal boron nitride ferromagnetic tunnelling contact that under a bias voltage can effectively inject spin-polarized holes into WSe₂, leading to a population imbalance between ±K valleys, as confirmed by density functional theory calculations and helicity-dependent electroluminescence measurements. Under an external magnetic field, we observe that the helicity of electroluminescence flips its sign and exhibits a hysteresis loop in agreement with the magnetic hysteresis loop obtained from reflective magnetic circular dichroism characterizations on Fe₃GeTe₂. Our results could address key challenges of valleytronics and prove promising for van der Waals magnets for magneto-optoelectronics applications.

过渡金属二硫属化物中谷自由度的电操纵是开发谷电子学的核心。为此，已利用铁磁接触，例如 Ga(Mn)As 和坡莫合金，将自旋极化载流子注入过渡金属二硫化物，以实现与谷相关的极化。然而，这些材料需要高外部磁场或复杂的外延生长步骤，限制了它们的实际应用。_{在这里，我们报告了基于单层WSe 2}和Fe ₃ GeTe ₂ /六方氮化硼铁磁隧道接触的范德华异质结构，在偏置电压下可以有效地将自旋极化空穴注入WSe ₂，导致±K谷之间的种群不平衡，如密度泛函理论计算和螺旋度相关的电致发光测量所证实的那样。在外部磁场下，我们观察到电致发光的螺旋性反转其符号并表现出与从Fe ₃ GeTe ₂上反射磁圆二色性表征获得的磁滞回线一致的磁滞回线。我们的结果可以解决谷电子学的关键挑战，并证明范德华磁体在磁光电子学应用中的前景。