Fig. 2: Raman spectra of LuH2±xNy.
a, Typical Raman spectra collected at ambient pressure for three samples (black, blue and green curves), and the data of nitrogen-doped lutetium hydride from ref. 1 (red curve) are shown for comparison. The samples are labelled SR1, SR2 and SR3, respectively. The tiny peaks of SR1 and SR2 below 140 cm−1 originate from the background signal of Raman spectrometer 1 (Extended Data Fig. 3). The band positions in the spectrum below 300 cm−1 have slightly smaller wavenumbers compared with those in ref. 1, indicating that the lattice constant of our sample is slightly larger. The results are also consistent with the lattice parameters obtained from XRD. This slight variation may be attributed to the different hydrogen and nitrogen concentrations in different samples. b, Raman spectra were collected at high pressures using Raman spectrometer 1 with a mixture of methanol, ethanol and water as the pressure medium for SR1. c, Evolution of band positions of Raman spectra under different pressures. The two curves correspond to the bands as indicated in b by red arrows. The red lines are guides for the eyes to show the change in the slopes. a.u., arbitrary unit.
