Wen Ting, Wang Yonggang, Li Nana, Zhang Qian, Zhao Yongsheng, Yang Wenge, Zhao Yusheng, Mao Ho-Kwang
Center for High Pressure Science and Technology Advanced Research (HPSTAR) , Beijing 100094 , China.
Department of Physics and Academy for Advanced Interdisciplinary Studies , Southern University of Science and Technology , Shenzhen 518055 , China.
J Am Chem Soc. 2019 Jan 9;141(1):505-510. doi: 10.1021/jacs.8b11269. Epub 2018 Dec 6.
Temperature-dependent switching between p- and n-type conduction is a newly observed phenomenon in very few Ag-based semiconductors, which may promote fascinating applications in modern electronics. Pressure, as an efficient external stimulus that has driven collective phenomena such as spin-crossover and Mott transition, is also expected to initialize a conduction-type switching in transition metal-based semiconductors. Herein, we report the observation of a pressure-driven dramatic switching between p- and n-type conduction in chalcopyrite CuFeS associated with a structural phase transition. Under compression around 8 GPa, CuFeS undergoes a phase transition with symmetry breakdown from space group I-42 d to space group I-4 accompanying with a remarkable volume shrinkage of the FeS tetrahedra. A high-to-low spin-crossover of Fe ( S = 2 to S = 0) is manifested along with this phase transition. Instead of pressure-driven metallization, a surprising semiconductor-to-semiconductor transition is observed associated with the structural and electronic transformations. Significantly, both photocurrent and Hall coefficient measurements confirm that CuFeS undergoes a reversible pressure-driven p- n conduction type switching accompanying with the structural phase transition. The absence of cationic charge transfer between copper and iron during the phase transition is confirmed by both X-ray absorption near-edge spectra (Cu/Fe, K-edge) and total-fluorescence-yield X-ray absorption spectra (Fe, K-edge) results, and the valence distribution maintains CuFeS in the high-pressure phase. The observation of an abrupt pressure-driven p- n conduction type switching in a transition metal-based semiconductor paves the way to novel pressure-responsive switching devices.
在极少数基于银的半导体中，温度依赖的p型和n型导电之间的切换是一种新观察到的现象，这可能会推动现代电子学中引人入胜的应用。压力作为一种有效的外部刺激，已驱动诸如自旋交叉和莫特转变等集体现象，预计它也会引发基于过渡金属的半导体中的导电类型切换。在此，我们报告了在与结构相变相关的黄铜矿CuFeS中观察到压力驱动的p型和n型导电之间的剧烈切换。在约8 GPa的压缩下，CuFeS经历了从空间群I-42 d到空间群I-4的对称破缺相变，同时FeS四面体有显著的体积收缩。随着这一相变，Fe发生了从高自旋（S = 2）到低自旋（S = 0）的转变。与压力驱动的金属化不同，观察到了与结构和电子转变相关联的令人惊讶的半导体到半导体的转变。重要的是，光电流和霍尔系数测量均证实，CuFeS伴随着结构相变经历了可逆的压力驱动的p-n导电类型切换。X射线吸收近边光谱（Cu/Fe，K边）和总荧光产额X射线吸收光谱（Fe，K边）结果均证实了相变过程中铜和铁之间不存在阳离子电荷转移，并且价态分布使CuFeS保持在高压相。在基于过渡金属的半导体中观察到突然的压力驱动的p-n导电类型切换，为新型压力响应开关器件铺平了道路。
