论文标题
温度引起的谐振拉曼散射的调制biLayer 2h-mos $ _ {2} $
Temperature induced modulation of resonant Raman scattering in bilayer 2H-MoS$_{2}$
论文作者
论文摘要
提出了从高质量的双层2H-mos $ _ {2} $封装在六边形BN薄片中的谐振拉曼散射的温度演变。观察到的共振拉曼散射光谱是由1.96 eV引发的，接近激发量共振，显示出丰富而独特的振动特征，否则在非谐波散射中未观察到。 1 $^{st} $和2 $^{nd} $订购声子模式的外观在从5 k到320 k的广泛温度下明确地观察到。这些频谱包括拉曼活性模式，$ e $ e $ e $ _ \ e $ _ \ textrm {1g}^{1g}^{2}^{2} $（$γ$）和γ$γ$γ$γ$γγ$）和A $ _ \ textrm {1G} $（$γ$）以及他们的Davydov-Split对应物，即$ e $ _ $ _ \ textrm {1U} $（$γ$）和B $ _ \ textrm {1U} $（$γ$）。拉曼散射光谱的温度演化带来了前进的关键观察，因为不同声子模式的综合强度曲线显示出不同的趋势。拉曼活性A $ _ {1G} $（$γ$）模式，该模式以$ t $ = 5〜k Quenches的温度升高，以$ t $ = 5〜K淬灭为主。令人惊讶的是，在室温下，B $ _ \ textrm {1U} $（$γ$）模式在双层中具有红外线活性，比其名义上的拉曼活性A $ _ \ textrm {1G} $（$γ$）的代码均高得多。
The temperature evolution of the resonant Raman scattering from high-quality bilayer 2H-MoS$_{2}$ encapsulated in hexagonal BN flakes is presented. The observed resonant Raman scattering spectrum as initiated by the laser energy of 1.96 eV, close to the A excitonic resonance, shows rich and distinct vibrational features that are otherwise not observed in non-resonant scattering. The appearance of 1$^{st}$ and 2$^{nd}$ order phonon modes is unambiguously observed in a broad range of temperatures from 5 K to 320 K. The spectrum includes the Raman-active modes, $i.e.$ E$_\textrm{1g}^{2}$($Γ$) and A$_\textrm{1g}$($Γ$) along with their Davydov-split counterparts, $i.e.$ E$_\textrm{1u}$($Γ$) and B$_\textrm{1u}$($Γ$). The temperature evolution of the Raman scattering spectrum brings forward key observations, as the integrated intensity profiles of different phonon modes show diverse trends. The Raman-active A$_{1g}$($Γ$) mode, which dominates the Raman scattering spectrum at $T$=5~K quenches with increasing temperature. Surprisingly, at room temperature the B$_\textrm{1u}$($Γ$) mode, which is infrared-active in the bilayer, is substantially stronger than its nominally Raman-active A$_\textrm{1g}$($Γ$) counterpart.
