Fig. 3: Matrix factorization results.

a Multivariate curve resolution (MCR) concept for angle-resolved polarized Raman spectroscopy, where the number of components, k, was determined to be two in the monoclinic (type B, MB) phase by singular-value decomposition (SVD). The data consist of a 20 × 1024 matrix, which can be decomposed into a 20 × 2 matrix (two angle profiles, p1(θ) and p2(θ)) and a 2 × 1024 matrix (two base spectra, I1(ν) and I2(ν)). b Angle-resolved polarized Raman spectra at X = 5 mm and Y ~ 7 mm, shown as a contour plot colored by intensity. c MCR data showing that p1(θ) and p2(θ) are numbers representing the proportion of I1(ν) and I2(ν), respectively, in the spectra at each θ.