Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0104237

Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+d

E. W. Hudson·K. M. Lang·V. Madhavan·S. H. Pan·H. Eisaki·S. Uchida·J. C. Davis
View original source ↗Read source document ↗Export metadata ↓

Abstract

In conventional superconductors, magnetic interactions and magnetic impurity atoms are destructive to superconductivity. By contrast, in some unconventional systems, e.g. superfluid 3He and superconducting UGe2, superconductivity or superfluidity is actually mediated by magnetic interactions. A magnetic mechanism has also been proposed for high temperature superconductivity (HTSC) in which an electron magnetically polarizes its environment resulting in an attractive pairing-interaction for oppositely polarized spins. Since a magnetic impurity atom would apparently not disrupt such a pairing-interaction, it has also been proposed that the weaker influences on HTSC of magnetic Ni impurity atoms compared to those of non-magnetic Zn are evidence for a magnetic mechanism. Here we use scanning tunneling microscopy (STM) to determine directly the influence of individual Ni atoms on the electronic structure of Bi2Sr2CaCu2O8+d. Two local d-wave impurity-states are observed at each Ni. Analysis of their energies surprisingly reveals that the primary quasiparticle scattering effects of Ni atoms are due to non-magnetic interactions. Nonetheless, we also demonstrate that a magnetic moment coexists with unimpaired superconductivity at each Ni site. We discuss the implications of these phenomena, and those at Zn, for the pairing-mechanism.

Explore related subjects

cond-mat.supr-concond-mat.str-el

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

E. W. Hudson, K. M. Lang, V. Madhavan, S. H. Pan, H. Eisaki, S. Uchida, J. C. Davis. 2001-04-12. Interplay of magnetism and high-Tc superconductivity at individual Ni impurity atoms in Bi2Sr2CaCu2O8+d. https://doi.org/10.1038/35082019

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Layer-Parity Control of the Superconducting Diode Effect in Monolayer NbSe$_2$

The superconducting diode effect is often associated with finite-momentum pairing, although model studies indicate that rectification reflects the asymmetry of the free energy about its minimum rather than the equilibrium pair momentum itself. Using a Wannier-based, self-consistent finite-$\mathbf Q$ Bogoliubov-de Gennes approach with a Fermi-surface-adaptive quadrature that converges the critical currents, we show that the layer parity and orientation of magnetic proximity select the diode response of monolayer NbSe$_2$. For in-plane exchange, the equilibrium pair momentum $\mathbf Q_{\rm eq}$ and the diode efficiency are both linear in the layer-odd exchange contrast: parallel proximity on the two Se sublayers is reciprocal, and antiparallel proximity doubles the response. An out-of-plane component separates the two observables. It leaves $\mathbf Q_{\rm eq}$ nearly unchanged but, through pair breaking, suppresses the efficiency by more than an order of magnitude and, at low temperature, reverses it. Purely out-of-plane exchange, for which $C_3$ symmetry forbids a helical term, keeps $\mathbf Q_{\rm eq}=0$ yet produces a trigonal diode effect, controlled by the layer-even exchange and larger than the in-plane one above $0.65$~meV at $0.58$~K. Magnetic layer parity thus selects between a helical and a trigonal diode channel. This trigonal channel provides a candidate intrinsic contribution to the field-free rectification reported in NbSe$_2$/CrBr$_3$. The model predicts that two-sided out-of-plane proximity cancels it when antiparallel and, at the same exchange per layer, enhances it about fourfold when parallel, in the computed range.

cond-mat.supr-con↗
arXiv2026

Chiral superconductivity on a closed Klein bottle: a chirality wall and its Majorana seam spectrum

We study a spinless $π$-flux lattice superconductor whose normal-state momentum-space fundamental domain is a Klein bottle. Within this model, a glide lift and a hidden antiunitary symmetry independently force the Bogoliubov--de Gennes (BdG) Chern number to vanish. A diagonal pairing breaks the antiunitary obstruction exactly when its real part is nonzero; this is necessary, not sufficient, for a chiral phase. We derive explicit Pfaffians determining Chern parity and identify three analytic families of gap closings in a real-pairing section. For a chiral state on a closed real-space Klein bottle, the prescribed pairing and gluing produce a $ΔC=2$ chirality wall. A translation-invariant unfolding resolves two co-propagating Majorana branches. Their finite-size levels depend on circumference and holonomy; the near-zero pair is lifted at first order by allowed local seam perturbations. A cut-cylinder control has the same low-energy channel count, so gluing reconnects existing gapless content. We also distinguish literal gluing from deck projection: particle--hole symmetry exchanges the deck eigenblocks, precluding their interpretation as independent BdG quotient Hamiltonians. Finite odd-frequency correlations track holonomy and local splitting, while cylinder and ordinary-wall controls show that their presence is not specific to Klein gluing. The contribution is a model-specific account of pairing compatibility, closed-surface seam spectra and finite correlations. The energy cost is evaluated for a fixed pairing background; neither a protected zero mode nor a self-consistent wall solution is claimed.

cond-mat.supr-con↗
arXiv2026

Electrically tunable superconducting dimensionality in stripe-ordered monolayer MoTe$_2$

Dimensionality governs the stability of collective quantum states, including whether Cooper pairs can establish the phase coherence required for superconductivity. In solids, however, electronic dimensionality is usually encoded in the crystal structure and is difficult to control reversibly. Here we show evidence that monolayer 1$T^{\prime}$-MoTe$_2$ develops a stripe charge-density wave that reorganizes its low-energy electronic states into quasi-one-dimensional channels. Raman spectroscopy and scanning tunneling microscopy identify the stripe order, whereas directional transport and tunneling spectroscopy reveal superconducting correlations confined to the stripe direction and insulating behavior perpendicular to it. Electrostatic doping weakens the transverse insulating response and drives the system into phase-coherent two-dimensional superconductivity. These results show that stripe charge order can reconfigure superconducting dimensionality and make it electrically tunable within a single crystalline layer.

cond-mat.supr-con↗