Abstract Cu2−xTe is mainly used as conductive back contacting material in CdTe solar cells. Unavoidable Cu deficiency has traditionally been considered as the primary cause of structural complexity, which limited its practical applicability. Here, combining X-ray diffraction (XRD) measurement with extensive swarm structure search, we identify the ambient structure of Cu1.875Te to be a P-3m1 phase, which transforms into a new defective I4/mmm phase at 2.9 GPa. Enthalpy calculations show that stoichiometric Cu2Te is expected to be synthesized above 5.3 GPa. The analysis of mechanical and dynamical stability implies that the high-pressure I4/mmm Cu2Te can potentially be stabilized to ambient conditions as a metastable material. Our results represent a significant step in understanding the crystal information of Cu2−xTe.

中文翻译：

---

Cu1.875Te 结构相变的高压研究

摘要 Cu2−xTe 主要用作 CdTe 太阳能电池中的导电背接触材料。传统上，不可避免的铜缺乏被认为是结构复杂的主要原因，这限制了其实际适用性。在这里，结合 X 射线衍射 (XRD) 测量和广泛的群结构搜索，我们确定 Cu1.875Te 的环境结构是 P-3m1 相，它在 2.9 GPa 时转变为新的有缺陷的 I4/mmm 相。焓计算表明化学计量的 Cu2Te 预计在 5.3 GPa 以上合成。机械和动态稳定性分析表明，高压 I4/mmm Cu2Te 可以作为亚稳态材料稳定到环境条件下。我们的结果代表了理解 Cu2-xTe 晶体信息的重要一步。