2018. 12-present: Dean, School of Mathematics and Physics, University of Science and Technology Beijing (USTB), China; 2019. 07-2019. 08: Visiting Scientist, University of Padova, Italy; 2015. 05-2015. 08: Foreign Guest Professor, Materials and Structure Laboratory, Tokyo Institute of Technology, Japan; 2013. 06-2018. 11: Vice Dean, Department of Physical Chemistry, University of Science and Technology Beijing (USTB), China; 2008. 01-2009. 04: Alexander von Humboldt Fellowship, Technische Universität Darmstadt, Germany; 2009. 07-present: Professor, University of Science and Technology Beijing (USTB), China; 2001. 09-2007.03: Ph.D, Department of Physical Chemistry, University of Science and Technology Beijing (USTB); 1997. 09-2001. 07: Bachelor, School of Material Science and Engineering, Hefei University of Technology.

1. Design of Giant Polarization in Ferroelectric Thin Films We have developed a new method of “interphase strain” for strain engineering to regulate lattice strain of ferroelectrics to achieve giant ferroelectric polarization by creating single-lattice-parameter epitaxial composite films. By using this new method, giant polarization in the super tetragonal PbTiO3/PbO thin film (L. X. Zhang, et al, Science 2018, 361, 494) and strong room-temperature ferroelectricity in the SrTiO3 thin films (T. Y. Li, et al, Adv. Mater. 2021, 2008316) have been achieved. 2. Mechanisms and New Systems of Negative Thermal Expansion Negative thermal expansion (NTE) is a counterintuitive thermophysical behavior, which shows unusual volume contraction upon heating. We have focused on the investigations of NTE mechanisms and exploring new NTE materials in the last two decades. We have developed a new NTE family of ferroelectrics, and proposed a new concept of “spontaneous volume ferroelectrostriction”. We have systematically studies the NTE mechanisms and designed new materials of open framework structures, such as oxides, ReO3-type fluorides, and Prussian blue cyanides. New methods are proposed for the chemical control of thermal expansion, such as ions or molecules intercalation, and local distortion. We have proposed a new concept of “average atomic volume” to explore new NTE materials for framework structure. We are also interested in NTE materials induced by magnetovolume effect. A series of new NTE alloys have been discovered by our group, including Tb(Co,Fe)2, (Hf,Nb)Fe2, Mn3Ge, and (Sc,Ti)Fe2. 3. Origin of High Performance Piezoelectrics Revealing the piezoelectric mechanism is a key point for the development of high-performance piezoelectric materials. In recently years, we have performed advanced in-situ diffraction technology to reveal the structure-property relationships in the perovskite-type piezoelectrics. We have identified electric field-induced single monoclinic phase in the classical Pb-based piezoelectrics, and observed its unique piezoelectric properties. We have revealed the critical role of electric-field-driven continuous polarization rotation in achieving giant piezoelectric response, and found that the reversible phase transformation at MPB is important to enhance piezoelectric performance. We have established the intrinsic relationship between crystal structure and piezoelectric performance in lead or lead-free ferroelectrics.

2 PhD student and 3~5 Master students per year

1. Tianyu Li,# Dengshi Qing,# Hui Liu, Shengdong Sun, Hao Li, Shuxian Hu, Shi Liu, Xianran Xing, Jun Chen,* Adv. Mater. 2021, 2008316. 2. Huajie Luo, Hui Liu, Shiqing Deng, Shuxian Hu, Lu Wang, Botao Gao, Shengdong Sun, Yang Ren, Lijie Qiao, Jun Chen,* Acta Mater. 2021, 208, 116711. 3. Naike Shi, Andrea Sanson, Qilong Gao, Qiang Sun, Yang Ren, Qngzhen Huang, Danilo Oliveir de Souza, Xianran Xing, Jun Chen,* J. Am. Chem. Soc. 2020, 142, 3088-3093. 4. Hui Liu, Longlong Fan, Shengdong Sun, Kun Lin, Yang Ren, Xiaoli Tan, Xianran Xing, Jun Chen,* Acta Mater. 2020, 184, 41-49. 5. Yuzhu Song, Jun Chen*, Xinzhi Liu, Chinwei Wang, Ji Zhang, Hui Liu, He Zhu, Lei Hu, Kun Lin, Shantao Zhang, Xianran Xing, J. Am. Chem. Soc. 2018, 140, 602. 6. Linxing Zhang, Jun Chen,* Longlong Fan, Oswaldo Diéguez, Jiangli Cao, Zhao Pan, Yilin Wang, Jinguo Wang, Moon Kim, Shiqing Deng, Jiaou Wang, Huanhua Wang, Jinxia Deng, Ranbo Yu, James F. Scott, Xianran Xing,* Science, 2018, 361, 494. 7. Lei Hu, Feiyu Qin, Andrea Sanson, Liang-Feng Huang, Zhao Pan, Qiang Li, Qiang Sun, Lu Wang, Fangmin Guo, Umut Aydemir, Yang Ren, Chengjun Sun, Jinxia Deng, Giuliana Aquilanti, James M. Rondinelli, Jun Chen,* Xianran Xing, J. Am. Chem. Soc. 2018, 140, 4477. 8. Hui Liu, Jun Chen,* Houbing Huang, Longlong Fan, Yang Ren, Zhao Pan, Jinxia Deng, Long-Qing Chen, Xianran Xing, Phys. Rev. Lett. 2018, 120, 055501. 9. Zhao Pan, Jun Chen*, Xingxing Jiang, Lei Hu, Runze Yu, Hajime Yamamoto, Takahiro Ogata, Yuichiro Hattori, Fangmin Guo, Xi’an Fan, Yawei Li, Guangqiang Li, Huazhi Gu, Yang Ren, Zheshuai Lin, Masaki Azuma, Xianran Xing, J. Am. Chem. Soc. 2017, 139, 14865. 10. Hui Liu, Jun Chen,* Longlong Fan, Yang Ren, Zhao Pan, K. V. Lalitha, Jürgen Rödel, Xianran Xing, Phys. Rev. Lett. 2017, 119, 017601.

11 doctoral students 17 postgraduates