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arXiv · 2206.06621

Exchange field enhanced upper critical field of the superconductivity in compressed antiferromagnetic EuTe2

Hualei Sun·Liang Qiu·Yifeng Han·Yunwei Zhang·Weiliang Wang·Chaoxin Huang·Naitian Liu·Mengwu Huo·Lisi Li·Hui Liu·Zengjia Liu·Peng Cheng·Hongxia Zhang·Hongliang Wang·Lijie Hao·Man-Rong Li·Dao-Xin Yao·Yusheng Hou·Pengcheng Dai·Meng Wang
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Abstract

We report high pressure studies on the C-type antiferromagnetic semiconductor EuTe2 up to 36.0 GPa. A structural transition from the I4/mcm to C2/m space group is identified at ~16 GPa. Superconductivity is discovered above ~5 GPa in both the I4/mcm and C2/m space groups. In the low-pressure phase (< 16 GPa), the antiferromagnetic transition temperature is enhanced with increasing pressure due to the enhanced magnetic exchange interactions. Magnetoresistance measurements indicate an interplay between the local moments of Eu2+ and the conduction electrons of Te 5p orbits. The upper critical field of the superconductivity is well above the Pauli limit. Across the structural transition to the high-pressure phase (> 16 GPa), EuTe2 becomes nonmagnetic and the superconducting transition temperature evolves smoothly with the upper critical field below the Pauli limit. Therefore, the high upper critical field of EuTe2 in the low-pressure phase is due to the exchange field compensation effect of the Eu magnetic order and the superconductivity in both structures may arise in the framework of the BCS theory.

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Hualei Sun, Liang Qiu, Yifeng Han, Yunwei Zhang, Weiliang Wang, Chaoxin Huang, Naitian Liu, Mengwu Huo, Lisi Li, Hui Liu, Zengjia Liu, Peng Cheng, Hongxia Zhang, Hongliang Wang, Lijie Hao, Man-Rong Li, Dao-Xin Yao, Yusheng Hou, Pengcheng Dai, Meng Wang. 2022-07-07. Exchange field enhanced upper critical field of the superconductivity in compressed antiferromagnetic EuTe2. https://arxiv.org/abs/2206.06621

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