报告人：杨文革
报告题目：Retaining the enhanced properties with pressure-induced lattice and electronic transitions to ambient conditions
报告时间：2025年4月28日（周一）上午10：30
报告地点：分析测试中心100会议室
主办单位：物理与电子工程学院、科学技术研究院
报告人简介：
杨文革，1995年毕业于武汉大学物理系，获理学博士。1995-1997洪堡学者在于利希研究中心合作研究准晶的结果与缺陷。1997-2013 先后在美国卡内基-梅隆大学、橡树岭国家实验室、卡内基研究院做博士后、客座研究员、研究员等职。2024年回国全职加入北京高压科学研究中心，入选国家级创新人才长期项目，任职研究员至今，2022起担任北京高压科学研究中心法人、主任。长期从事材料在极端条件下物质的结构与物性的探索，开发同步辐射在高压条件下的研究，发表300余篇SCI学术论文。
报告摘要：
Pressure is an effective tool to tune the crystal and electronic structures of materials, which turns out with large property modulation. With a proper kinetical energy phase transition pathway, the tailored properties achieved at high pressure could be retained to ambient pressure for industry applications. Here we want to focus on two systems to demonstrate the great potential for pressure engineered materials with enhanced properties. 1)Transparent conducting oxides (TCO) with high electrical conductivity and high visible light transparency are desired for a wide range of high-impact engineering. Here, we demonstrate the pressure engineering strategy to modulate the lattice and electronic and optical properties on an indium titanium oxides (ITiO) TCO. Strikingly, after compression–decompression treatment on the ITiO, a highly transparent and metastable phase with two orders of magnitude enhancement in conductivity is synthesized from an irreversible phase transition. Moreover, this phase possesses previously unattainable filter efficiency on hazardous blue light up to 600 °C, providing potential for healthcare-related applications with strong thermal stability up to 200 °C. 2) Multiferroic ferroelectric photovoltaic (FPV) materials, which integrate magnetic and ferroelectric properties, are of paramount importance for optoelectronic and photovoltaic applications. We choose the multiferroic material BaFe4O7 with a unique FeO4 tetrahedral and FeO6 octahedral interleaving arrangement. We witness that pressure induces charge transfer from Fe in the tetrahedral sites to Fe in the octahedral sites, leading to charge disproportionation that narrows the bandgap from 2.12 eV to 0.53 eV, positioning it within the optimal range for photovoltaic applications. Simultaneously, pressure-induced polar distortion in the FeO6 octahedron enhances the symmetry breaking of the lattice, resulting in a threefold increase in ferroelectric polarization at pressures between 20-25 GPa. This concurrent modulation of the bandgap and ferroelectric polarization leads to a twofold enhancement in ferroelectric photocurrent. Remarkably, the optimized bandgap (1.42 eV) and enhanced polarization remain stable upon releasing the pressure to ambient conditions. From these two case studies, we present the great potential for enhancing electric, optical, energy harvest performance via pressure-induced electronic structure and crystal structure, offering a promising avenue for the development of high-performance, functional materials.