Figure 2. Experimental and calculated phonons.

(a) Raman spectra of the bulk sample with incident Laser I and Laser II along the c- and b-axes at room temperature, respectively. The calculated Raman spectrum is plotted for comparison. (b) Calculated phonon dispersion curve along the Γ-Y-X-Γ-Z direction in the orthorhombic Brillouin zone (BZ), and the vibrational density of states (DOS) for WTe₂ bulk at the equilibrium volume. The blue and green curves are the optical and acoustic vibrational branches, respectively.