Jahn-Teller distortions induced strong negative thermal expansion inα-Cu2V2O7
7
Issued Date
2026-01-30
Resource Type
eISSN
13616633
Scopus ID
2-s2.0-105029066866
Pubmed ID
41534115
Journal Title
Reports on Progress in Physics Physical Society Great Britain
Volume
89
Issue
1
Rights Holder(s)
SCOPUS
Bibliographic Citation
Reports on Progress in Physics Physical Society Great Britain Vol.89 No.1 (2026)
Suggested Citation
Hao X., Zhao S., Gao Q., Qiao Y., Sanson A., Matan K., Gitgeatpong G., Sun Q., Guo J., Jin F., He L., Kawaguchi S., Liang E., Chen J. Jahn-Teller distortions induced strong negative thermal expansion inα-Cu2V2O7. Reports on Progress in Physics Physical Society Great Britain Vol.89 No.1 (2026). doi:10.1088/1361-6633/ae3853 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/114906
Title
Jahn-Teller distortions induced strong negative thermal expansion inα-Cu2V2O7
Author's Affiliation
Università degli Studi di Padova
Zhengzhou University
University of Science and Technology Beijing
Institute of Physics Chinese Academy of Sciences
Hainan University
Faculty of Science, Mahidol University
Japan Synchrotron Radiation Research Institute
Ministry of Higher Education, Science, Research and Innovation
Spallation Neutron Source Science Center
Phranakhon Rajabhat University
Zhengzhou University
University of Science and Technology Beijing
Institute of Physics Chinese Academy of Sciences
Hainan University
Faculty of Science, Mahidol University
Japan Synchrotron Radiation Research Institute
Ministry of Higher Education, Science, Research and Innovation
Spallation Neutron Source Science Center
Phranakhon Rajabhat University
Corresponding Author(s)
Other Contributor(s)
Abstract
Negative thermal expansion (NTE) refers to volume contraction upon heating, but the intrinsic complexity of its physical mechanisms presents a fundamental challenge.α-Cu2V2O7exhibits significant anisotropic NTE over a wider temperature range; however, its NTE mechanism has not been clearly elucidated. Herein, we systematically investigate the NTE mechanism ofα-Cu2V2O7using neutron powder diffraction, synchrotron radiation x-ray diffraction, and temperature- and pressure-dependent Raman spectra, and density functional theory calculations across 5-800 K. The structure exhibits a second-order Jahn-Teller (SOJT) effect, which is the primary cause of off-centering within the quasi-CuO6octahedra. As temperature increases, the SOJT effect weakens, reducing the distortion of the driving force for off-centering; this causes the Cu atoms to shift in opposite directions, increasing symmetry. The anti-off-centering displacement of the Cu atoms toward the O4(long)atoms in the quasi-CuO6octahedra compresses the Cu···Cu zigzag chains and reduces the spacing between orthogonal chains, resulting in the NTE behavior ofα-Cu2V2O7. This study reveals a novel mechanism whereby the SOJT effect governs the displacement and symmetry of Cu atoms, providing crucial insight into the origin of NTE behavior inα-Cu2V2O7. These findings could help the community advance the understanding of NTE in anisotropic materials.