Surface d-orbital order in intermetallic compound
Abstract
Orbital order describes a quantum state where occupied orbitals line up in a periodic pattern. While orbital physics plays a fundamental and universal role in strongly correlated electron systems, the existence and particularly the band structure fingerprint of orbital order remain a long-standing mystery. Here, we report the discovery of rare earth 5d-orbital order developed by the surface states of intermetallic compound Tb2CoAl4Ge2. Angle-resolved photoemission spectroscopy reveals characteristic nematic features like Fermi surface deformation and band split. These experimental observations can be described by a ferro-orbital order term in the mean-field Hamiltonian. The structural and magnetic origin of such order is excluded by systematic high-resolution neutron powder diffraction and scanning tunnelling microscopy measurements. Our results provide strong evidence for a pure surface orbital order scenario avoiding complications from structural distortion as in colossal magnetoresistance manganites, magnetic order as in iron-based superconductors, and charge transfer p-orbital order in cuprates.
Cite
@article{arxiv.2605.26426,
title = {Surface d-orbital order in intermetallic compound},
author = {Zhanyang Hao and Haohao Sheng and Wanru Ma and Wengen Zheng and Yongqing Cai and Zijuan Xie and Wanlin Cheng and Zuowei Liang and Wu Xie and Wenjuan Zhao and Chen Liu and Zhibin Su and Junhao Lin and Liusuo Wu and Zhengtai Liu and Mao Ye and Ji Dai and Massimo Tallarida and Shengtao Cui and Yogendra Kumar and Kenya Shimada and Kenichi Ozawa and Shuki Torii and Kazuhiro Mori and Yue Xie and Junze Deng and Jiaou Wang and Xuetao Zhu and Jiandong Guo and Jiawei Mei and Zhenyu Wang and Xianhui Chen and Ping Miao and Zhijun Wang and Chaoyu Chen},
journal= {arXiv preprint arXiv:2605.26426},
year = {2026}
}
Comments
4 main figures, 10 extended figures