Spectral Visualization of Excitonic Pair Breaking at Individual Impurities in Ta2Pd3Te5

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Hauptverfasser: Yang, Lianzhi, Wu, Deguang, Zhang, Hanbo, Zhang, Yao, Deng, Xiutong, Zhang, Chao, Zhai, Tianyou, Zhang, Wenhao, Shi, Youguo, Wang, Rui, Liu, Chaofei, Fu, Ying-Shuang
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Veröffentlicht: 2026
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author Yang, Lianzhi
Wu, Deguang
Zhang, Hanbo
Zhang, Yao
Deng, Xiutong
Zhang, Chao
Zhai, Tianyou
Zhang, Wenhao
Shi, Youguo
Wang, Rui
Liu, Chaofei
Fu, Ying-Shuang
author_facet Yang, Lianzhi
Wu, Deguang
Zhang, Hanbo
Zhang, Yao
Deng, Xiutong
Zhang, Chao
Zhai, Tianyou
Zhang, Wenhao
Shi, Youguo
Wang, Rui
Liu, Chaofei
Fu, Ying-Shuang
contents Excitonic insulators host the condensates of bound electron-hole pairs, offering a platform for studying correlated bosonic quantum states. Yet, how macroscopic coherence emerges from locally collapsed pairing remains elusive. Here, using scanning tunnelling spectroscopy, we report the impurity-induced pair breaking in an excitonic insulator Ta2Pd3Te5. Individual Te vacancies are found to generate a pair of spectral peaks within the excitonic gap. Their energies depend sensitively on the defect configurations and are continuously tunable by tip electric field, indicating controllable impurity scatterings. Spectral mapping shows spatially anisotropic and electronically coupled electron-hole components of the subgap states. These observations, together with mean-field modelling, suggest an excitonic pair-breaking origin. In the strongly electron-hole imbalanced region, a secondary pair-breaking effect, manifesting as an additional pair of subgap states with distinctly lower energies, can emerge, presenting the interplay of pairing breakings with different excitonic order parameters. Our findings demonstrate the spectroscopic 'fingerprint' of local excitonic depairing at the atomic level, offering a crucial clue to the critical behavior across excitonic condensation.
format Preprint
id arxiv_https___arxiv_org_abs_2601_01096
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spectral Visualization of Excitonic Pair Breaking at Individual Impurities in Ta2Pd3Te5
Yang, Lianzhi
Wu, Deguang
Zhang, Hanbo
Zhang, Yao
Deng, Xiutong
Zhang, Chao
Zhai, Tianyou
Zhang, Wenhao
Shi, Youguo
Wang, Rui
Liu, Chaofei
Fu, Ying-Shuang
Strongly Correlated Electrons
Excitonic insulators host the condensates of bound electron-hole pairs, offering a platform for studying correlated bosonic quantum states. Yet, how macroscopic coherence emerges from locally collapsed pairing remains elusive. Here, using scanning tunnelling spectroscopy, we report the impurity-induced pair breaking in an excitonic insulator Ta2Pd3Te5. Individual Te vacancies are found to generate a pair of spectral peaks within the excitonic gap. Their energies depend sensitively on the defect configurations and are continuously tunable by tip electric field, indicating controllable impurity scatterings. Spectral mapping shows spatially anisotropic and electronically coupled electron-hole components of the subgap states. These observations, together with mean-field modelling, suggest an excitonic pair-breaking origin. In the strongly electron-hole imbalanced region, a secondary pair-breaking effect, manifesting as an additional pair of subgap states with distinctly lower energies, can emerge, presenting the interplay of pairing breakings with different excitonic order parameters. Our findings demonstrate the spectroscopic 'fingerprint' of local excitonic depairing at the atomic level, offering a crucial clue to the critical behavior across excitonic condensation.
title Spectral Visualization of Excitonic Pair Breaking at Individual Impurities in Ta2Pd3Te5
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2601.01096