## 3 Results and Discussion  
Figure 2 presents the zero-field polarized-Raman spectra of the monolayer WS\({}_{2}\) on SiO\({}_{2}\)/Si and Au film, respectively. The Raman spectra of WS\({}_{2}\)/SiO\({}_{2}\) exhibit obvious dependence on polarization configurations, as shown in Figure 2a. The line shape of the Raman spectra of the VV spectrum of WS\({}_{2}\)/SiO\({}_{2}\) resumes that of monolayer WS\({}_{2}\) in previous literature [11,30]. When the polarization configuration changes from VV to VH, the overall intensity of the spectrum is significantly weakened. After fitting with Lorentzians, five peaks are identified in the range of 250-450 cm\({}^{-1}\) for the Raman spectra of WS\({}_{2}\)/SiO\({}_{2}\), which is consistent with previous literature [31]. Among them, three peaks are worthy of special attention: the second-order resonant peaks involving longitudinal acoustic mode 2 LA(M); the in-plane \(E^{\prime}\) vibration mode of two S atoms in the plane in reverse motion with W atom; the out-of-plane \(A^{\prime}_{1}\) vibration mode of two S atoms moving backward out of plane [24,32]. At VV configuration, \(E^{\prime}\) mode is just a shoulder peak on the right side of 2 LA(M) mode in the Raman spectra of WS\({}_{2}\)/SiO\({}_{2}\). And the peak intensities of 2 LA(M) and \(A^{\prime}_{1}\) are much higher than that of E\({}^{\prime}\) mode. In contrast, the intensities of the 2 LA(M) and \(A^{\prime}_{1}\) modes are obviously weaker relative to \(E^{\prime}\) under VH configuration. The \(E^{\prime}\) mode emerges as an isolated peak, whereas the 2 LA(M) mode shrinks significantly. The polarization dependence for the Raman spectra of WS\({}_{2}\)/SiO\({}_{2}\) follows the Raman selection rules (RSRs) for WS\({}_{2}\)[24,33]. On the other hand, the Raman spectra of WS\({}_{2}\)/Au exhibit prominent different polarization dependent behaviors, as shown in Figure 2b. In sharp contrast to the Raman spectra of WS\({}_{2}\)/SiO\({}_{2}\), the spectra lineshapes of WS\({}_{2}\)/Au exhibit obvious distinctions. The intensity of 2 LA(M) and \(A^{\prime}_{1}\) modes are enhanced prominently and become comparable to that of \(E^{\prime}\) mode. Especially in the VH configuration, the intensity of 2 LA(M) is still hardening. The Raman spectra in Figure 2b clearly evidence the breaking of RSRs on WS\({}_{2}\)/Au, which could be associated with the strong coupling between the plasmon and phonons in WS\({}_{2}\)[34]. As it is well known, the localized electromagnetic (EM) field at close vicinity of the Au NPs can be enhanced due to the LSPR effect under an excitation [35]. The intensity enhancement of the Raman modes for WS\({}_{2}\)/Au is attributed to the surface enhanced Raman scattering  
Figure 1: (**a**) Optical image for WS\({}_{2}\) on SiO\({}_{2}\)/Si substrate. (**b**) Magnified SEM image of WS\({}_{2}\) on Au film. (**c**) Schematic illustration for the polarized-Raman setup under magnetic field. (SERS) process as a result of the enhanced EM field [28]. In addition to the SERS process, other physical mechanisms cannot be excluded from the distinct polarized-Raman spectra of WS\({}_{2}\)/Au. The strain induced by Au NPs underneath also contributes to the intensity enhancement of 2 LA(M) mode [36; 37]. It has been demonstrated that the A\({}_{1}\)-symmetry mode is very sensitive to the doping effect [38; 39]. For the hybrids composed of TMDs and noble metal NPs, the \"hot carriers\" are generated and transfer from NPs to WS\({}_{2}\) flake under the light illumination [40; 41]. Employing ultrafast transient absorption spectroscopy with pumping photon energy below the indirect bandgap of the rippled MoS\({}_{2}\) quadrilayer, [PERSON] et al. directly demonstrated a plasmon-induced charge transfer between Au and MoS\({}_{2}\)[42]. As reported by [PERSON] and coauthors, the Au NPs acted as dopants to WS\({}_{2}\) in the plasmonic hybrid nanostructures [28]. The broadening and enhancement of \(A^{\prime}_{1}\) mode observed in this work is closed related with the electronic doping effect from Au film.