Superconductivity at 22.3 K in Compressed Sodium-intercalated Graphite

Fuente: arXiv
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Main Authors: Huang, Ming-Xing, Liu, Yuan-Qing, Hao, Chun-Mei, Shao, Xi, An, Tingwei, Yang, Guochun, Gao, Yufei, Wang, Shaojie, Wang, Lin, Xu, Bo, Ke, Feng, Zhou, Xiang-Feng, Tian, Yongjun
Format: Preprint
Published: 2025
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author Huang, Ming-Xing
Liu, Yuan-Qing
Hao, Chun-Mei
Shao, Xi
An, Tingwei
Yang, Guochun
Gao, Yufei
Wang, Shaojie
Wang, Lin
Xu, Bo
Ke, Feng
Zhou, Xiang-Feng
Tian, Yongjun
author_facet Huang, Ming-Xing
Liu, Yuan-Qing
Hao, Chun-Mei
Shao, Xi
An, Tingwei
Yang, Guochun
Gao, Yufei
Wang, Shaojie
Wang, Lin
Xu, Bo
Ke, Feng
Zhou, Xiang-Feng
Tian, Yongjun
contents Graphite intercalation compounds (GICs) have long been recognized as promising candidates for high-temperature superconductivity by intercalation or charge doping, yet experimental progress has stalled with transition temperatures (Tc) limited to 11.5 K at ambient pressure and 15.1 K at 7.5 GPa in calcium-intercalated graphite over decades. Here, we report robust superconductivity in sodium-intercalated graphite with Tc of 22.3 K, as demonstrated by clear zero-resistance behavior. Our approach involves simply room-temperature grinding of graphite with sodium, followed by slight compression up to 7.1 GPa, circumventing complex synthesis procedures. Through synchrotron X-ray diffraction combined with first-principles calculations, we identify the major superconducting phase as an orthorhombic stage-2 GIC structure with slightly over-stoichiometric composition (Na1+xC8). Electron-phonon coupling calculations reveal that superconductivity primarily emerges from the interactions between out-of-plane carbon electrons and low-frequency Na/C vibrations.The enhancement in Tc establishes sodium as superior for achieving higher-Tc in GICs and illustrates promising pathway for further optimization through compositional and structural tuning.
format Preprint
id arxiv_https___arxiv_org_abs_2509_23137
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Superconductivity at 22.3 K in Compressed Sodium-intercalated Graphite
Huang, Ming-Xing
Liu, Yuan-Qing
Hao, Chun-Mei
Shao, Xi
An, Tingwei
Yang, Guochun
Gao, Yufei
Wang, Shaojie
Wang, Lin
Xu, Bo
Ke, Feng
Zhou, Xiang-Feng
Tian, Yongjun
Superconductivity
Graphite intercalation compounds (GICs) have long been recognized as promising candidates for high-temperature superconductivity by intercalation or charge doping, yet experimental progress has stalled with transition temperatures (Tc) limited to 11.5 K at ambient pressure and 15.1 K at 7.5 GPa in calcium-intercalated graphite over decades. Here, we report robust superconductivity in sodium-intercalated graphite with Tc of 22.3 K, as demonstrated by clear zero-resistance behavior. Our approach involves simply room-temperature grinding of graphite with sodium, followed by slight compression up to 7.1 GPa, circumventing complex synthesis procedures. Through synchrotron X-ray diffraction combined with first-principles calculations, we identify the major superconducting phase as an orthorhombic stage-2 GIC structure with slightly over-stoichiometric composition (Na1+xC8). Electron-phonon coupling calculations reveal that superconductivity primarily emerges from the interactions between out-of-plane carbon electrons and low-frequency Na/C vibrations.The enhancement in Tc establishes sodium as superior for achieving higher-Tc in GICs and illustrates promising pathway for further optimization through compositional and structural tuning.
title Superconductivity at 22.3 K in Compressed Sodium-intercalated Graphite
topic Superconductivity
url https://arxiv.org/abs/2509.23137