TaRh ₂ B ₂ and NbRh ₂ B ₂ : Superconductors with a chiral noncentrosymmetric crystal structure

Abstract

Two superconductors with a new chiral noncentrosymmetric crystal structure and Hc2 values above the Pauli limit.

Multigap superconductivity in chiral noncentrosymmetric TaRh2B2

“…We obtain good fits to the data, as measured by χ (5) nm, which is higher than the value calculated from magnetization [1,25].…”

“…We show that TaRh 2 B 2 can be best described using a two-gap (s + s)-wave model. We clearly demonstrate that TaRh 2 B 2 is a type-II superconductor with an upper critical field, μ 0 H c2 = 15.2(1) T, that is significantly higher than previous reported [1] and well above the Pauli limit.…”

“…TaRh 2 B 2 and NbRh 2 B 2 are both NCS superconductors with a chiral structure and have the potential to exhibit similar exciting physics. The first report on this material [1] shows TaRh 2 B 2 has a trigonal structure (space group P 3 1 ), with a T c of 5.8 K and an upper critical field that exceeds the Pauli limit. Here, we have used a combination of muon spectroscopy and heat capacity to probe the nature of the superconducting state of TaRh 2 B 2 .…”

“…The discovery of two noncentrosymmetric (NCS) superconductors with chiral structures, TaRh 2 B 2 and NbRh 2 B 2 [1], has added a new twist to an already exciting area of superconductivity research [2,3]. For all superconductors, the topology of the electronic band structure, along with the underlying crystal structure, play vital roles in determining the superconducting properties of the material.…”

“…Polycrystalline samples of TaRh 2 B 2 were prepared from the constituent elements using the synthesis method described earlier [1,25]. Powder x-ray diffraction (PXRD) performed using a Panalytical X-Pert Pro diffractometer showed the material forms with a trigonal P 3 1 structure and lattice parameters a = 4.6984(2)Å and c = 8.7338(5)Å.…”