Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/9907159

Pseudo-gap features of intrinsic tunneling in (HgBr_2)-Bi2212 single crystals

A. Yurgens·D. Winkler·T. Claeson·Seong-Ju Hwang·Jin-Ho Choy
View original source ↗Read source document ↗Export metadata ↓

Abstract

The c-axis tunneling properties of both pristine Bi2212 and its HgBr$_2$ intercalate have been measured in the temperature range 4.2 - 250 K. Lithographically patterned 7-10 unit-cell heigh mesa structures on the surfaces of these single crystals were investigated. Clear SIS-like tunneling curves for current applied in the $\it c$-axis direction have been observed. The dynamic conductance d$I/$d$V(V)$ shows both sharp peaks corresponding to a superconducting gap edge and a dip feature beyond the gap, followed by a wide maximum, which persists up to a room temperature. Shape of the temperature dependence of the {\it c}-axis resistance does not change after the intercalation suggesting that a coupling between $\rm CuO_2$-bilayers has little effect on the pseudogap.

Explore related subjects

cond-mat.supr-con

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A. Yurgens, D. Winkler, T. Claeson, Seong-Ju Hwang, Jin-Ho Choy. 1999-07-10. Pseudo-gap features of intrinsic tunneling in (HgBr_2)-Bi2212 single crystals. https://doi.org/10.1142/s0217979299003878

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

KEEP EXPLORING

Related papers

arXiv2026

Field-induced first order quantum phase transition of the superconducting order parameter in Ising superconductors with Rashba spin-orbit coupling

Ising superconductors have attracted significant attention recently due to their resilience against magnetic fields far beyond the Pauli-paramagnetic limit as well as their broader role as a platform for exploring the interplay of spin-orbit coupling, valley degrees of freedom and superconducting pairing in two-dimensional materials. Their protection against external magnetic field relies on strong Ising spin-orbit coupling, which originates from in-plane inversion symmetry breaking. Due to the heavy atom nature of Ising SCs, a smaller but sizable Rashba SOC can arise from gating or interfacial effects. Here, we study Rashba spin-orbit coupling within a two-valley model of Ising superconductors with an attractive $s$-wave interaction. We show that Rashba SOC induces a first order quantum phase transition in Ising superconductors. At low temperatures, this means the superconducting order parameter vanishes abruptly in the vicinity of the quantum critical point. This effect, however, disappears at high temperatures. Our findings demonstrate that the low- and high temperature physics of Ising SCs are quantitatively and qualitatively different in the two-valley model.

cond-mat.supr-con↗
arXiv2026

Nonlocal Cooper pairs in finite topological superconductors and their relation to Majorana nonlocality

We identify two fundamental properties of the Gor'kov Green's function of finite one-dimensional topological superconductors. In the low-frequency (low-energy) regime, the normal and anomalous Green's functions become identical up to a phase factor. Moreover, they exhibit pronounced nonlocality: the components connecting the two ends of the system grow exponentially with system length, whereas the local components at either end vanish in the zero-frequency limit. These striking features signify the emergence of unconventional nonlocal Cooper pairs associated with a nonlocal fermionic mode composed of hybridized Majorana end modes. The nonlocal Cooper pairs are directly linked to fermion parity and to the nonlocal transport properties of finite topological superconductors. By uncovering the unusual nonlocal properties of the Gor'kov Green's function, our analysis advances the understanding of Majorana nonlocality, a key concept in topological quantum computation.

cond-mat.supr-con↗
arXiv2026

Collective phase modes in twisted $d$-wave superconducting bilayers

Twisted cuprate bilayers have been predicted to host high-temperature chiral $d+id'$ superconductivity, originating from higher-order Josephson coupling processes. In such two-dimensional superconducting systems, long-wavelength fluctuations in the phase of the superconducting order parameter constitute gapless collective modes and therefore remain significant even at zero temperature. Here, we perform a theoretical analysis of the low-energy phase fluctuations in twisted $d$-wave superconducting bilayers within a self-consistent harmonic approximation, systematically retaining Josephson coupling to all orders. We demonstrate that higher-order Josephson coupling processes lead to nontrivial modifications of the phase dynamics. The momentum-resolved summand of the relative-phase stiffness is nonzero even in the normal state because interlayer tunneling explicitly breaks the intralayer U(1) symmetry, but its momentum integral vanishes for the continuum dispersion. The relative-phase stiffness is smaller in the $d+id'$ phase than in the $d$-wave phase, while the overall-phase stiffness has the opposite behavior. Furthermore, phase fluctuations strongly soften the Josephson plasma frequency near a twist angle of $45^\circ$ and also substantially reduce the Josephson critical current.

cond-mat.supr-con↗