Superconductivity Emerging from a Weyl Semimetal Candidate under Pressure
Meiling Jin1*, Peng Yu2, Changzeng Fan3, Gang Xu4, Zheng Liu5, Changqing Jin6, Jinlong Zhu1*
1Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing, 100094, China
2School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China
3Yanshan University, Qinhuangdao, 066004, China
4Wuhan National High Magnetic Field Center, Huazhong University of Science & Technolog, Wuhan, 430074, China
5Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
6Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
Keywords: high pressure, Weyl semimetal, superconductivity
*e-mail: meiling.jin@hpstar.ac.cn
jinlong.zhu@hpstar.ac.cn
The topological properties have received strong interest both theoretically and experimentally in recent years. Insulators can be classified into conventional insulators and topological insulators with protection by time-reversal symmetry. By analogy from insulator to metal, semimetal can be topologically classified as trivial and nontrivial in terms of electronic structure, including Weyl, Dirac, and node-line semimetal [1]. Weyl fermion have been observed experimentally in Weyl semimetal as low-energy excitation, exhibiting a host of quantum phenomena such as topological Fermi arc and chiral anomaly. Remarkably, Weyl fermion is robust while carrying currents, giving rise to exceptionally high mobility [2].
Turning a Weyl semimetal into a superconducting state is a viable pathway towards unconventional superconductor which could potentially be topologically nontrivial and host exotic Majorana modes. Transition metal dichalcogenides have attracted tremendous research interest due to pressure-enhanced superconductivity in Weyl semimetal candidate WTe2 and MoTe2. The ternary transition metal tellurides NbIrTe4, an ordered variant of the WTe2 is a newly predicted time-reversal invariant type-Άς Weyl semimetal [3]. Here we report that superconductivity emerges in NbIrTe4 with a critical transition temperature of 2.5 K at a critical pressure of ca. 2 GPa, which is enhanced up to 5.75 K at 16 GPa. Hall coefficient measurements demonstrated that elevating pressure increases the population of electron carriers and triggers superconducting transition. Significantly, a sign change of the Hall coefficient was observed near the critical pressure of superconducting transition, which may due to the tilt of the Weyl cone tuned by strain on crystal lattice. Our discovery of superconductivity in NbIrTe4 under high pressure will stimulate further investigations on superconductivity and Majorana fermions in Weyl semimetals.
[1] Yan, B., & Felser, C. Annual Review of Condensed Matter Physics, 2017, 8, 337-354.
[2] Jia, Shuang, Su-Yang Xu, and M. Zahid Hasan. Nature materials, 2016, 15, 11, 1140-1144.
[3] Li, Lei, et al. Physical Review B, 2017, 96, 2, 024106.