高压下碲化镓的电学性质研究

Study on the Electrical Properties of Gallium Telluride under High Pressure

为了探究高压下GaTe的结构相变与电输运性质,研究利用金刚石对顶砧装置在0 GPa~30 GPa压力范围内对样品进行原位电阻率、交流阻抗谱测量以及第一性原理计算。实验结果显示,在压力范围内,样品电阻率整体下降了9个数量级;在4.8 GPa压力后,电阻率迅速下降,直到11.4 GPa压力后电阻率减小缓慢并趋于平稳。变温电阻率实验表明,在压力小于10 GPa时,电阻率随温度升高而减小呈现半导体特性;在压力大于11.7 GPa时,电阻率随温度升高而升高呈现金属特性。交流阻抗谱测量结果表明,在样品高压电输运过程中晶粒占主要贡献,电导机制为电子导电。根据第一性原理计算发现,在4.5 GPa压力时发生相变,C2/m相为直接带隙半导体,而Fm3m相则表现为金属特性。

In order to investigate the structural phase transition and electrical transport properties of GaTe under high pressure,the article aims to use a diamond anvil device to perform in-situ resistivity,AC impedance spectroscopy measurements as well as first principles calculations on the sample in the pressure range of 0 GPa to 30 GPa.The experimental results suggest that within the pressure range,the overall resistivity of the sample decreased by 9 orders of magnitude;After a pressure of 4.8 GPa,the resistivity decreases rapidly until it decreases slowly and stabilizes after a pressure of 11.4 GPa.The variable temperature resistivity experiment shows that at pressure lower than 10 GPa,the resistivity decreases with temperature and exhibits semiconductor characteristics;at pressure higher than 11.7 GPa,the resistivity increases with temperature and exhibits metallic properties.The measurement results of AC impedance spectroscopy indicate that grains make a major contribution during the high-voltage electrical transport process of the samples,and the conductivity mechanism is electron conduction.According to first principles calculations,it's found that the phase transition occurs at a pressure of 4.5 GPa.In addition,the C2/m phase is a direct bandgap semiconductor,while the Fm3m phase exhibits metallic properties.