Strong correlation behavior and Strong coupling superconductivity in (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix with the rich magnetic element Ni

Zijun Huang; Tong Li; Longfu Li; Rui Chen; Zaichen Xiang; Shuangyue Wang; Jingjun Qin; Yucheng Li; Lingyong Zeng; Dinghua Bao; Huixia Luo

arXiv · 2507.21793

Strong correlation behavior and Strong coupling superconductivity in (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix with the rich magnetic element Ni

Zijun Huang·Tong Li·Longfu Li·Rui Chen·Zaichen Xiang·Shuangyue Wang·Jingjun Qin·Yucheng Li·Lingyong Zeng·Dinghua Bao·Huixia Luo

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Abstract

Searching for new superconductors, especially unconventional superconductors, has been studied extensively for decades but remains one of the major outstanding challenges in condensed matter physics. Medium/high-entropy alloys (MEAs-HEAs) are new fertile soils of unconventional superconductors and generate widespread interest and questions on the existence of superconductivity in highly disordered materials. Here, we report on the effect of Ni-doped on the crystal structure and superconductivity properties of strongly coupled TiHfNbTa MEA. XRD results indicate that the maximum solid solution of (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix is about 7.7%. Resistivity, magnetic susceptibility, and specific heat measurements demonstrated that (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix HEAs are all bulk type-II superconductors and follow the trend of the increase of Tc with the increase of Ni-doped contents. The specific heat jump of all (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix are much larger than the BCS value of 1.43, suggesting all these HEAs are strongly coupled superconductors. Additionally, large Kadawaki-Woods ratio values suggest that there is a strong electron correlation effect in this system. The (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix HEA system is a new ideal material platform for the study of strong correlation behavior and strongly coupled superconductivity, which provides an insight into the physics of high-temperature superconductors or other unconventional superconductors.

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Zijun Huang, Tong Li, Longfu Li, Rui Chen, Zaichen Xiang, Shuangyue Wang, Jingjun Qin, Yucheng Li, Lingyong Zeng, Dinghua Bao, Huixia Luo. 2025-07-29. Strong correlation behavior and Strong coupling superconductivity in (Ti1/4Hf1/4Nb1/4Ta1/4)1-xNix with the rich magnetic element Ni. https://arxiv.org/abs/2507.21793

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