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Main Authors: Cao, Zi-Yu, Peng, Di, Choi, Seokmin, Lan, Fujun, Yu, Lan, Zhang, Enkang, Xing, Zhenfang, Liu, Yuxin, Zhang, Feiyang, Luo, Tao, Chen, Lixing, Hong, Vuong Thi Anh, Paek, Seung-Yeop, Jang, Harim, Xie, Jinghong, Liu, Huayu, Lou, Hongbo, Zeng, Zhidan, Ding, Yang, Zhao, Jun, Liu, Cailong, Park, Tuson, Zeng, Qiaoshi, Mao, Ho-kwang
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.12606
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author Cao, Zi-Yu
Peng, Di
Choi, Seokmin
Lan, Fujun
Yu, Lan
Zhang, Enkang
Xing, Zhenfang
Liu, Yuxin
Zhang, Feiyang
Luo, Tao
Chen, Lixing
Hong, Vuong Thi Anh
Paek, Seung-Yeop
Jang, Harim
Xie, Jinghong
Liu, Huayu
Lou, Hongbo
Zeng, Zhidan
Ding, Yang
Zhao, Jun
Liu, Cailong
Park, Tuson
Zeng, Qiaoshi
Mao, Ho-kwang
author_facet Cao, Zi-Yu
Peng, Di
Choi, Seokmin
Lan, Fujun
Yu, Lan
Zhang, Enkang
Xing, Zhenfang
Liu, Yuxin
Zhang, Feiyang
Luo, Tao
Chen, Lixing
Hong, Vuong Thi Anh
Paek, Seung-Yeop
Jang, Harim
Xie, Jinghong
Liu, Huayu
Lou, Hongbo
Zeng, Zhidan
Ding, Yang
Zhao, Jun
Liu, Cailong
Park, Tuson
Zeng, Qiaoshi
Mao, Ho-kwang
contents The recent discovery of superconductivity in pressure-stabilized bulk La3Ni2O7-delta, with a critical temperature (Tc) exceeding 77 K, has opened a new frontier in high-temperature superconductivity research beyond cuprates. Yet, the superconducting gap amplitude and symmetry, the key parameters to characterize a superconductor, remain elusive due to the overwhelming challenges of gap studies under high pressure. Here, we introduce in situ directional point-contact spectroscopy conducted under truly hydrostatic pressure, enabling the direct mapping of the superconducting gap in pressurized La3Ni2O7-delta single crystals. Depending on the junction orientation, differential conductance (dI/dV) spectra exhibit distinct V-shaped quasiparticle features and a sharp zero-bias peak, indicating a predominant d-wave-like pairing symmetry. Measurement of the c-axis gap amplitude Delta yields a gap-to-Tc ratio of 2Delta/kBTc = 4.2(5), positioning La3Ni2O7-delta firmly among unconventional, nodal high-Tc superconductors. These findings set stringent constraints on theoretical models for nickelate superconductors and establish a robust spectroscopic approach for understanding superconductors under extreme pressures.
format Preprint
id arxiv_https___arxiv_org_abs_2509_12606
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Direct Observation of d-Wave Superconducting Gap Symmetry in Pressurized La3Ni2O7-delta Single Crystals
Cao, Zi-Yu
Peng, Di
Choi, Seokmin
Lan, Fujun
Yu, Lan
Zhang, Enkang
Xing, Zhenfang
Liu, Yuxin
Zhang, Feiyang
Luo, Tao
Chen, Lixing
Hong, Vuong Thi Anh
Paek, Seung-Yeop
Jang, Harim
Xie, Jinghong
Liu, Huayu
Lou, Hongbo
Zeng, Zhidan
Ding, Yang
Zhao, Jun
Liu, Cailong
Park, Tuson
Zeng, Qiaoshi
Mao, Ho-kwang
Superconductivity
The recent discovery of superconductivity in pressure-stabilized bulk La3Ni2O7-delta, with a critical temperature (Tc) exceeding 77 K, has opened a new frontier in high-temperature superconductivity research beyond cuprates. Yet, the superconducting gap amplitude and symmetry, the key parameters to characterize a superconductor, remain elusive due to the overwhelming challenges of gap studies under high pressure. Here, we introduce in situ directional point-contact spectroscopy conducted under truly hydrostatic pressure, enabling the direct mapping of the superconducting gap in pressurized La3Ni2O7-delta single crystals. Depending on the junction orientation, differential conductance (dI/dV) spectra exhibit distinct V-shaped quasiparticle features and a sharp zero-bias peak, indicating a predominant d-wave-like pairing symmetry. Measurement of the c-axis gap amplitude Delta yields a gap-to-Tc ratio of 2Delta/kBTc = 4.2(5), positioning La3Ni2O7-delta firmly among unconventional, nodal high-Tc superconductors. These findings set stringent constraints on theoretical models for nickelate superconductors and establish a robust spectroscopic approach for understanding superconductors under extreme pressures.
title Direct Observation of d-Wave Superconducting Gap Symmetry in Pressurized La3Ni2O7-delta Single Crystals
topic Superconductivity
url https://arxiv.org/abs/2509.12606