Unconventional magnetization in the multiphase superconductor PdBi${}_2$

Abstract

Unconventional superconductors have specific signatures in their magnetic properties, such as intrinsic magnetization at interfaces and around defects and fractional and multiquanta vortices, with much attention focused on heavy fermion and high-$T_c$ superconductors. Here, we report the observation of highly anomalous magnetization in $\beta$-PdBi${}_2$, a layered superconductor previously shown to exhibit a magnetic field-induced transition from s-wave to nodal p-wave superconductivity at a transition field $H^{\ast }\sim$0.1 T ($H_{C1}<H^{\ast }<H_{C2}$). This transition is driven by the coupling between spin-polarized electronic bands and the in-plane magnetic field. In the unconventional phase (above $H^{\ast }$) we observe three striking features: strictly linear and non-hysteretic dc magnetization, a sharp drop in the ac susceptibility when the field is applied parallel to the ab-plane, and a pronounced anisotropy in the magnetic response between parallel and perpendicular field orientations. We show that these features are directly correlated with the expected transition to the nodal p-wave state and propose that the unusual magnetization behavior can be explained by a transition from a conventional vortex lattice in the low-field s-wave phase to a domain structure corresponding to spatial phase separation into superconducting (p-wave) and normal domains above $H^{\ast }$. Our work identifies new experimental signatures of unconventional multiphase superconductivity, offering an insight into the magnetic-field response of nodal states.

22 pages, 9 figures

References in corpus (27)

• Time-Reversal Symmetry Breaking Superconductivity in Sr2RuO4
• Hidden spin polarization in inversion-symmetric bulk crystals
• Nearly Isotropic superconductivity in (Ba,K)Fe2As2
• Tuning Ising superconductivity with layer and spin-orbit coupling in two-dimensional transition-metal dichalcogenides
• Properties of the Ideal Ginzburg-Landau Vortex Lattice
• Observation of half-height magnetization steps in Sr2RuO4
• Extreme magnetic field-boosted superconductivity
• Anisotropy of the Upper Critical Field and Critical Current in Single Crystal MgB${}_2$
• Quasi-two-dimensional organic superconductors: a review
• Field-induced transition from even to odd parity superconductivity in CeRh${}_2$As${}_2$
• Topologically protected surface states in a centrosymmetric superconductor beta-PdBi2
• Unexpected two-fold symmetric superconductivity in few-layer NbSe${}_2$
• Unusual upper critical field of the ferromagnetic superconductor UCoGe
• Psuedo-isotropic upper critical field in cobalt-doped SrFe2As2 epitaxial films
• Magnetic field dependence of the density of states in the multiband superconductor $\beta$-Bi${}_2$Pd
• Vortex lattices and broken time reversal symmetry in the topological superconductor UPt3
• Thermodynamics of the interplay between magnetism and high-temperature superconductivity
• Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum
• Single gap superconductivity in beta-Bi2Pd
• Spin-Triplet Vortex State in the Topological Superconductor CuxBi2Se3
• Superconductors in realistic geometries: Geometric edge barrier versus pinning
• Type-I superconductivity in Al${}_6$Re
• Observation of a gel of quantum vortices in a superconductor at very low magnetic fields
• Nearly isotropic superconductivity in layered Weyl semimetal WTe${}_2$ at 98.5 kbar
• Lattices of double-quanta vortices and chirality inversion in $p_x+i{p}_y$ superconductors
• Subsurface bending and reorientation of tilted vortex lattices in the bulk due to Coulomb-like repulsion at the surface
• Multiphase superconductivity in PdBi2