Abstract：In recent years SnO has been increasingly used in optical and electrical applications. Raman spectroscopic in situ tests and first-principle calculations were applied to investigate the structural and electronic properties of SnO under high-pressure conditions to broaden the application scope of SnO. The results of the characterization of SnO are as follows: the scanning electron microscopy results show that the selected SnO samples are lamellar stacks with transverse dimensions, and the whole is in the shape of a flower; the X-ray diffraction patterns indicate that the crystal structure of the SnO samples is a tetragonal crystal system structure (space group P4/nmm) at room temperature and pressure. The structural properties of SnO samples under high pressure have been investigated using Mao-Bell Diamond anvil cell and in situ Raman spectroscopy, and the results show that there are four Raman vibrational modes (A1g, B1g, E1g and E2g) of SnO at atmospheric pressure. A1g characterizes the vibration parallel to thez-axis in the plane of the Sn—Sn bond; B1g characterizes the vibration parallel to thez-axis in the plane of the O—O bond; andEg characterizes the vibration of Sn—O atoms in the plane of the intra-layer polarization, which are located near the wave numbers 211, 350, 113, and 460 cm-1, respectively, with the peaks 113 and 211 cm-1 being SnO characteristic peaks. During the pressurization of the SnO sample system to 12.5 GPa, the pressure causes Sn's intermolecular and atomic spacing to decrease, resulting in the shortening of the Sn—O bond length. When the atoms undergo telescopic vibration, the shortened bond length increases bond energy. Thus, the active Raman vibrational modes (E1g and A1g) shift toward the high-frequency direction. As the system pressure continues to increase, the lattice is distorted, the inelastic scattering intensity decreases, and the peaks broaden; when the pressure is increased to 8 GPa, the vibrational mode peaks of E1g and A1g near 125 and 216 cm-1 decrease dramatically; when the pressure is increased to 10 GPa, the two characteristic peaks disappear completely, and it is inferred that amorphization of the substance occurs in the non-hydrostatic pressure environment at 8~10 GPa. When the system was pressurized to 12.5 GPa, no new peaks still appeared in the spectra, indicating that the amorphous state was stable under high pressure. Subsequently, the system was depressurized, and theE1g and A1g modes of SnO reappeared after depressurization to 3 GPa, indicating that the sample regained the crystal structure at low pressure. The intensity of the unloading to atmospheric pressure characteristic peaks are located at 110 and 209 cm-1, respectively, in agreement with the unpressurized data, proving that the high-pressure phase transition behavior of SnO is reversible. To further understand the effect of pressure on the electrical properties of SnO, the electronic properties of SnO at atmospheric pressure and experimentally speculated amorphization pressure (8 GPa) were calculated using the first-principles approach. The effect of pressure on the electrical conductivity of SnO was investigated through the change in band gap width of SnO before and after amorphization. The results show that SnO is an indirect bandgap semiconductor with a bandgap of 0.43 eV at atmospheric pressure, there is no overlap of the density of states near the Fermi energy level, and SnO displays metallic properties at 8 GPa when the material is metalized due to the overlap of the density of states of the O-p, Sn-s, and Sn-p orbitals of SnO at the Fermi energy level, which leads to the closure of the bandgap. In this paper, the Raman spectroscopic and electrical properties of SnO under high-pressure environments have been investigated, enriching the study of the physicochemical properties of this material under extreme conditions. The results of this paper further improve the investigation of the structural and electrical properties of SnO under high pressure, expanding the scope of its research in the field of high pressure, and the results will be helpful for the experimental study of SnO under high-pressure and its application under high pressure.
Key words：SnO; Raman spectroscopy; Diamond anvil cell; The first principles; Electronic properties
刘 涛，黄宇轩，高金金，王世霞. SnO高压结构稳定性和电学性能研究[J]. 光谱学与光谱分析, 2025, 45(01): 82-87.
LIU Tao, HUANG Yu-xuan, GAO Jin-jin, WANG Shi-xia. Study of Structural Stability and Electrical Properties Under High Pressure of SnO. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(01): 82-87.
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