Superconductivity in the Medium-Entropy Alloy TiVNbTa with a Body-Centered Cubic Structure
Kuan Li, Xunwu Hu, Ruixin Guo, Wenrui Jiang, Lingyong Zeng, Longfu Li, Peifeng Yu, Kangwang Wang, Chao Zhang, Shu Guo, Ruidan Zhong, Tao Xie, Dao‐Xin Yao, Huixia Luo
Abstract
Here, we report the TiVNbTa medium-entropy alloy (MEA) superconductor with the mixed 3d–5d elements synthesized by an arc-melting method. The TiVNbTa material has a body-centered cubic structure with the cell parameter a = 3.2547(3) Å. The superconducting properties of TiVNbTa were studied by resistivity, magnetic susceptibility, and specific heat measurements. The experimental results show that the bulk superconducting phase transition temperature of TiVNbTa is about 4.65 K, and the upper and lower critical fields are 49.3(4) mT and 5.9(5) T, respectively, which indicates that TiVNbTa is a type-II superconductor. First-principles calculations show that the d electrons of Ti, V, Nb, and Ta atoms play a significant role near the Fermi level. The results show that TiVNbTa is a traditional s-wave superconductor (Δ C el /γ T c = 1.60(2), λ ep = 0.76(3)).