Temperature and concentration dependence of the parameters of the 127I NQR spectrum of the (BiI3)1–x(PbI2)x mixed layered semiconductor

The results of investigations of the temperature coefficients of the parameters of the 127 I NQR spectrum of the (BiI 3 ) 1– x (PbI 2 ) x mixed layered semiconductor in the temperature range 77–150 K are reported. It is shown that, at low PbI 2 contents, x ≤ 0.08, the temperature coefficients of the quadrupole coupling constants and asymmetry parameter for 127 I nuclei remain unchanged, while at x = 0.20 and T = 77 K, the NQR spectrum undergoes significant changes. Based on the measurements performed, it is concluded that, at PbI 2 contents of x ≤ 0.08, the quasi-two-dimensional pattern of the vibrational states persist.