Figure 4 PCA loading maps of band excitation piezoresponse force spectroscopy (BEPS) data. (a) First loading map associated with the principal
components in Figure 3 of the BEPS data. (b) Second loading map associated with the principal components in Figure 3 of the BEPS data. (c)
Third loading map associated with the principal components in Figure 3 of the BEPS data. (d) Fourth loading map associated with the principal
components in Figure 3 of the BEPS data.