Enhanced Superconductivity and Upper Critical Field in Ta‐Doped Weyl Semimetal Td‐MoTe2

• Published in: Advanced materials (Weinheim) 2023-05, Vol.35 (19), p.e2207841-n/a
• Main Authors: Zhang, Yong, Fei, Fucong, Liu, Ruxin, Zhu, Tongshuai, Chen, Bo, Qiu, Tianyu, Zuo, Zewen, Guo, Jingwen, Tang, Wenchao, Zhou, Lifan, Xi, Xiaoxiang, Wu, Xiaoshan, Wu, Di, Zhong, Zhicheng, Song, Fengqi, Zhang, Rong, Wang, Xuefeng
• Format: Article
• Language: English
• Subjects: Broken symmetry; Chalcogenides; Critical field (superconductivity); Magnetoresistance; Magnetoresistivity; Materials science; MoTe 2; phase transition; Phase transitions; Single crystals; Spintronics; Superconductivity; topological Weyl semimetal; Topology; Transition metal compounds; Transition temperature; upper critical field
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202207841

2D transition metal dichalcogenides are promising platforms for next‐generation electronics and spintronics. The layered Weyl semimetal (W,Mo)Te2 series features structural phase transition, nonsaturated magnetoresistance, superconductivity, and exotic topological physics. However, the superconducting critical temperature of the bulk (W,Mo)Te2 remains ultralow without applying a high pressure. Here, the significantly enhanced superconductivity is observed with a transition temperature as large as about 7.5 K in bulk Mo1−xTaxTe2 single crystals upon Ta doping (0 ≤ x ≤ 0.22), which is attributed to an enrichment of density of states at the Fermi level. In addition, an enhanced perpendicular upper critical field of 14.5 T exceeding the Pauli limit is also observed in Td‐phase Mo1−xTaxTe2 (x = 0.08), indicating the possible emergence of unconventional mixed singlet–triplet superconductivity owing to the inversion symmetry breaking. This work provides a new pathway for exploring the exotic superconductivity and topological physics in transition metal dichalcogenides. The superconducting transition temperature is greatly enhanced to be as large as 7.5 K in bulk Mo1−xTaxTe2 single crystals, which is attributed to an enrichment of density of states at the Fermi level. We also find the enhanced upper critical field beyond the Pauli limit in Ta‐doped Weyl semimetal Td‐MoTe2, which is likely due to the mixed singlet–triplet superconductivity.