Ubiquitous Interplay between Charge Ordering and High-Temperature Superconductivity in Cuprates (1312.1347v1)

Abstract: Besides superconductivity, copper-oxide high temperature superconductors are susceptible to other types of ordering. We use scanning tunneling microscopy and resonant elastic x-ray scattering measurements to establish the formation of charge ordering in the high-temperature superconductor Bi2Sr2CaCu2O8+x. Depending on the hole concentration, the charge ordering in this system occurs with the same period as those found in Y-based or La-based cuprates, and displays the analogous competition with superconductivity. These results indicate the similarity of charge organization competing with superconductivity across different families of cuprates. We observe this charge ordering to leave a distinct electron-hole asymmetric signature (and a broad resonance centered at +20 meV) in spectroscopic measurements, thereby indicating that it is likely related to the organization of holes in a doped Mott insulator.

• The paper identifies a distinct electron-hole asymmetric signature at +20 meV, emphasizing the competition between charge ordering and superconductivity in underdoped cuprates.
• It employs STM and REXS techniques on Bi-2212 samples to quantify a non-dispersive modulation at δ ≈ 0.3 and a broad CO feature between 0 and 50 meV.
• The findings suggest a universal charge ordering mechanism that influences superconductivity, paving the way for novel technological applications and further research.

Analyzing the Interplay Between Charge Ordering and Superconductivity in Cuprates

The research presented in "Ubiquitous Interplay between Charge Ordering and High-Temperature Superconductivity in Cuprates" explores the relationships between charge ordering (CO) and high-temperature superconductivity (HTS) in cuprates, aiming to enhance understanding of the mechanisms underlying superconductivity in these materials. The investigation utilizes scanning tunneling microscopy (STM) and resonant elastic x-ray scattering (REXS) measurements to examine Bi-2212 samples, contributing to the broader discourse on the interplay of electron interactions in underdoped cuprates.

Key Observations and Methodology

The research revolves around the utilization of STM and REXS to investigate the Bi-2212 system, notorious for its comprehensive spectroscopic information on Fermi surfaces and occupied electronic states. Notably, the investigations highlight a distinct electron-hole asymmetric signature, with CO manifesting in spectroscopic measurements as a broad resonance centered at +20 meV above the chemical potential. This is particularly interesting as it contrasts with previous ARPES observations which did not denote any significant band folding associated with CO along the Cu-O bond direction in the system.

Numerical and Experimental Findings

The findings indicate a correlation between charge ordering and specific electron interactions in the cuprates. Key numerical results are conspicuous in the identification of a non-dispersive modulation with δ ≈ 0.3, intrinsic to CO within the Bi-2212 system, and the broad CO feature observed between 0 and 50 meV. The REXS measurements corroborate the presence of this CO peak, which shows enhancement at higher temperatures and a gradual weakening below the superconducting transition temperature $T_c$. This suggests an intricate competition between superconductivity and charge ordering, with low temperatures favoring superconductivity, evidenced by the emergence of conventional Bogoliubov-de Gennes quasiparticle interference (BdG-QPI) patterns in the STM data.

Theoretical Implications and Broader Context

The resemblance of CO wavevectors across different families of cuprates posits a possible universal mechanism underlying charge ordering in these materials. The researchers speculate whether there exists a unified charge ordering mechanism despite variations in crystalline structures, proposing further investigation into the impact of strong electronic correlations and proximity to the Mott insulator phase. The distinctive particle-hole asymmetry in charge orderings potentially arises from complex electronic correlations, a hypothesis in alignment with predicted tunneling phenomena in doped Mott insulators.

Practical Implications and Future Directions

Practically, the paper prompts a refined approach towards harnessing these fundamental material properties in deciding applications of high-temperature superconductors. It suggests that understanding the dynamic competition between CO and HTS might provide novel avenues for enhancing the technological utilization of cuprates, such as in energy-efficient power transmission or magnetic field generation applications.

Future research could explore dissecting the role of Mott insulators and exploring possible correlations between superconductivity and electronic heterogeneities in various cuprate families. Such studies could offer additional insights into managing and leveraging the unique electronic properties of these materials.

In conclusion, this paper contributes substantively to the understanding of high-temperature superconductivity, presenting a compelling case for a universal charge ordering mechanism and setting the groundwork for future exploration into the intricacies of electron interactions in cuprates.