Superconductivity in noncentrosymmetric YPtBi under pressure

Abstract

We report a high-pressure single-crystal study of the non-centrosymmetric superconductor YPtBi (Tc = 0.77 K). Magnetotransport measurements show a weak metallic behavior with a carrier concentration n ≃ 2.2 × 10 19 cm −3 . Resistivity measurements up to p = 2.51 GPa reveal superconductivity is promoted by pressure. The reduced upper critical field Bc2(T ) curves collapse onto a single curve, with values that exceed the model values for spin-singlet superconductivity. The Bc2 data point to an odd-parity component in the superconducting order parameter, in accordance with predictions for non-centrosymmetric superconductors.

Pressure-induced superconductivity in the three-dimensional topological Dirac semimetal Cd3As2

“…It may come from a two-band Fermi surface topology as in MgB 2 , [35][36][37] or an unconventional superconducting state as in heavy-fermion compound UBe 13 . 38 11,[39][40][41] We notice that no superconductivity was observed up to 13.43 GPa in an earlier pressure study of Cd 3 As 2 single crystal. 42 The reason may be that their sample is slightly different from ours, and pressure higher than 13.43 GPa is needed to induce superconductivity.…”

High-pressure study of the basal-plane anisotropy of the upper critical field of the topological superconductor SrxBi2Se3

“…The pressure cell was attached to the cold plate of a 3 He refrigerator (Heliox, Oxford Instruments) equipped with a superconducting solenoid (B max = 14 T). The effective pressure was determined in previous experiments 24,25 and the maximum pressure reached is 2.2 GPa. Low temperature, T = 0.24 − 10 K, resistance measurements were performed using a low-frequency lock-in technique with low excitation currents (I ≤ 100 µA).…”

Ballistic transport in one-dimensional random dimer photonic crystals

“…Magnetotransport data taken on single crystals grown from Bi flux show semi-metallic [1,2] or weakmetallic [10] [10], respectively. The low carrier concentration results in a very small value of the Sommerfeld coefficient in the specific heat: γ ≤ 0.1 mJ/molK 2 [19].…”

“…Hitherto, the superconducting state of YPtBi has mainly been characterized by resistivity measurements (in field) [1,10]. A sharp drop to zero resistance is observed at T c = 0.77 K. The upper critical field, B c2 attains a value of 1.2 T in the limit T → 0, which translates into a superconducting coherence length ξ = 17 nm.…”

“…A topological insulator has the intriguing property that its interior is an insulator, while the surface harbors metallic states that are protected by topology [8,9]. Indeed, YPtBi [1,2,10], LaPtBi [11] and LuPtBi [12,13], are low carrier systems and the transport properties reveal semi-metallic behaviour. For LuPtBi, surface metallic states have been observed in ARPES experiments [14], but solid evidence for a topological non-trivial state has not been provided to date.…”