摘要
Exploiting the valley degrees of freedom as information carriers provides new opportunities for the development of valleytronics.Monolayer transition metal dichalcogenides(TMDs)with broken space-inversion symmetry exhibit emerging valley pseudospins,making them ideal platforms for studying valley electronics.However,intervalley scattering of different energy valleys limits the achievable degree of valley polarization.Here,we constructed WSe_(2)/yttrium iron garnet(YIG)heterostructures and demonstrated that the interfacial magnetic exchange effect on the YIG magnetic substrate can enhance valley polarization by up to 63%,significantly higher than that of a monolayer WSe_(2)on SiO_(2)/Si(11%).Additionally,multiple sharp exciton peaks appear in the WSe_(2)/YIG heterostructures due to the strong magnetic proximity effect at the magnetic-substrate interface that enhances exciton emission efficiency.Moreover,under the effect of external magnetic field,the magnetic direction of the magnetic substrate enhances valley polarization,further demonstrating that the magnetic proximity effect regulates valley polarization.Our results provide a new way to regulate valley polarization and demonstrate the promising application of magnetic heterojunctions in magneto-optoelectronics.
基金
The authors would like to acknowledge the National Natural Science Foundation of China(Nos.61775241,62090035,and U19A2090)
the Hunan Province Key Research and Development Project(No.2019GK2233)
the Hunan Provincial Science Fund for Distinguished Young Scholars(No.2020JJ2059)
the Youth Innovation Team of CSU(No.2019012)
the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)
the Science and Technology Innovation Basic Research Project of Shenzhen(No.JCYJ20190806144418859)
the Postdoctoral Science Foundation of China(No.2022M713546)
The authors would also like to express their gratitude to the High-Performance Complex Manufacturing Key State Lab Project,Central South University(No.ZZYJKT2020-12)
the Australian Research Council(ARC)Discovery Project(No.DP180102976)for their support of Z.W.L.C.T.W.acknowledges support from the National Natural Science Foundation of China(No.11974387)
the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB33000000)
H.H.Z.is grateful for the support from the Postdoctoral Science Foundation of China(No.2022M713546).
