Andreev-reflection spectroscopy of SrPt3P single crystals
Abstract
The interplay between inversion symmetry breaking and superconducting pairing mechanisms is a long-standing puzzle of solid-state physics. Ternary platinum phosphide SrPt3P is an excellent case study in this regard, since it shares the distorted anti-perovskite crystal structure of non-centrosymmetric superconductor CePt3Si but preserves the inversion symmetry center, enabling a direct comparison between the two compounds. Despite intense scrutiny, the superconducting pairing strength, gap symmetry, and magnitude of SrPt3P remain an open question. Here, we study the gap structure of high-quality SrPt3P single crystals with Tc = 8.6 K by using point-contact Andreev-reflection spectroscopy. The spectra systematically showed symmetric conductance maxima and a zero-bias minimum, as is typical of fully gapped superconductors, and dips at finite voltage Vdip due to the local transition of the contact region to the resistive state. In contacts with high resistance, where the dips fall sufficiently far from the gap features, the conductance curves can be well fitted with a single isotropic s-wave gap. The temperature dependence Δ(T) of the gap amplitude extracted from the fit is in good agreement with the one predicted by the BCS theory, with a zero-temperature mean value Δ(0)=1.88±0.08 meV, and a mean gap ratio 2Δ/kBTc = 5.2±0.2.
Versions
Related
- Multiple Andreev Reflection Spectroscopy of Spin-Resolved Proximity States
- Tuning Andreev reflection and conductance in proximitized nanowires through the spin-orbit field direction
- Comment on "Andreev Reflection to Probe Momentum-Dependent Spin Polarization in Altermagnet CrSb"
- Topologically protected perfect crossed Andreev reflection in flux-engineered quantum wire junctions
- Emergent Andreev Reflection from a Lattice Duality Defect
BibTeX
@misc{stepanov2026andreevreflection,
title = {{Andreev-reflection spectroscopy of SrPt3P single crystals}},
author = {Valeriy A. Stepanov and Nikolai D. Zhigadlo and Erik Piatti and Dario Daghero},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.19851},
eprint = {2610.19851},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.19851},
}
RIS
TY - UNPB
TI - Andreev-reflection spectroscopy of SrPt3P single crystals
AU - Valeriy A. Stepanov
AU - Nikolai D. Zhigadlo
AU - Erik Piatti
AU - Dario Daghero
PY - 2026
DA - 2026/10/14
PB - arXiv
DO - 10.48550/arxiv.2610.19851
UR - https://arxiv.org/abs/2610.19851
AB - The interplay between inversion symmetry breaking and superconducting pairing mechanisms is a long-standing puzzle of solid-state physics. Ternary platinum phosphide SrPt_3P is an excellent case study in this regard, since it shares the distorted anti-perovskite crystal structure of non-centrosymmetric superconductor CePt_3Si but preserves the inversion symmetry center, enabling a direct comparison between the two compounds. Despite intense scrutiny, the superconducting pairing strength, gap symmetry, and magnitude of SrPt_3P remain an open question. Here, we study the gap structure of high-quality SrPt_3P single crystals with T_c = 8.6 K by using point-contact Andreev-reflection spectroscopy. The spectra systematically showed symmetric conductance maxima and a zero-bias minimum, as is typical of fully gapped superconductors, and dips at finite voltage V_dip due to the local transition of the contact region to the resistive state. In contacts with high resistance, where the dips fall sufficiently far from the gap features, the conductance curves can be well fitted with a single isotropic s-wave gap. The temperature dependence Δ(T) of the gap amplitude extracted from the fit is in good agreement with the one predicted by the BCS theory, with a zero-temperature mean value Δ(0)=1.88±0.08 meV, and a mean gap ratio 2Δ/k_BT_c = 5.2±0.2.
ER -