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Abstract Realization of large effective phonon magnetic moment in monolayer MoS₂has established an important route for exploring intriguing magnetic phenomena in a nonmagnetic material. The sizable coupling between the orbital transition and the circularly polarized phonon results in the large effective phonon magnetic moment. In this work, using magneto-Raman spectroscopy, we investigate substitutional doping of magnetic atoms as a tuning knob of the electronic and phononic properties of MoS₂. We show that Fe-doping polarizes the spin of the conduction bands and introduces a localized Fe band underneath the conduction band. As a result, an additional orbital transition between the Mo 4dand Fe 3dstates emerges, producing an orbital-phonon hybridized mode at 283 cm⁻¹. Our magnetic field dependent measurements demonstrate that this new mode carries 2.8 ${\mu }_{\mathrm{B}}$effective phonon magnetic moment, which is comparable to that of the undoped MoS₂. Moreover, even though a long-range magnetic order is absent in Fe-doped MoS₂, the local magnetic moment of Fe modifies the nature of the spin fluctuation, producing monotonically increasing quasielastic scattering spectral weight as temperature decreases. Our results highlight two-dimensional dilute magnetic semiconductors synthesized by substitutional doping as a promising material platform to manipulate the phonon magnetic moment through orbital-phonon coupling. 

Recent helicity−resolved magneto−Raman spectroscopy measurement demonstrates large effective phonon magnetic moments of ~2.5 $$\mu_B$$ in monolayer MoS$$_2$$, highlighting resonant excitation of bright excitons as a feasible route to activate $$\Gamma$$−point circularly polarized phonons in transition metal dichalcogenides. However, a microscopic picture of this intriguing phenomenon remains lacking. In this work, we show that an orbital transition between the split conduction bands ($$\Delta_0$$ = 4 meV) of MoS$$_2$$ couples to the doubly degenerate $$E^{′′}$$ phonon mode ($$\Omega_0$$ = 33 meV), forming two hybridized states. Our phononic and electronic Raman scattering measurements capture these two states: (i) one with predominantly phonon contribution in the helicity−switched channels, and (ii) one with primarily orbital contribution in the helicity−conserved channels. An orbital−phonon coupling model successfully reproduces the large effective magnetic moments of the circularly polarized phonons and explains their thermodynamic properties. Strikingly, the Raman mode from the orbital transition is superimposed on a strong quasi−elastic scattering background, indicating the presence of spin fluctuations. As a result, the electrons excited to the conduction bands through the exciton exhibit paramagnetic behavior although MoS$$_2$$ is generally considered as a non-magnetic material. By depositing nanometer−thickness nickel thin films on monolayer MoS$$_2$$, we tune the electronic structure so that the A exciton perfectly overlaps with the 633 nm laser. The optimization of resonance excitation leads to pronounced tunability of the orbital−phonon hybridized states. Our results generalize the orbital−phonon coupling model of effective phonon magnetic moments to material systems beyond the paramagnets and magnets. 

Realization of large effective phonon magnetic moment in monolayer MoS$$_2$$ has established an important route for exploring intriguing magnetic phenomena in a nonmagnetic material. The sizable coupling between the orbital transition and the circularly polarized phonon results in the large effective phonon magnetic moment. In this work, using magneto-Raman spectroscopy, we investigate substitutional doping of magnetic atoms as a tuning knob of the electronic and phononic properties of MoS$$_2$$. We show that Fe-doping polarizes the spin of the conduction bands and introduces a localized Fe band underneath the conduction band. As a result, an additional orbital transition between the Mo 4$$d$$ and Fe 3$$d$$ states emerges, producing an orbital-phonon hybridized mode at 283 cm$$^{-1}$$. Our magnetic field dependent measurements demonstrate that this new mode carries 2.8 $$\mu_B$$ effective phonon magnetic moment, which is comparable to that of the undoped MoS$$_2$$. Moreover, even though a long-range magnetic order is absent in Fe-doped MoS$$_2$$, the local magnetic moment of Fe modifies the nature of the spin fluctuation, producing monotonically increasing quasielastic scattering spectral weight as temperature decreases. Our results highlight two-dimensional dilute magnetic semiconductors synthesized by substitutional doping as a promising material platform to manipulate the phonon magnetic moment through orbital-phonon coupling.