Unraveling the Complex, Intertwined Electron Phases in a Superconductor

October 28, 2015

A rendering of the charge density wave. [Credit: Brookhaven National Laboratory]

In a Letter in Nature Physics, an international team of reserchers from Brookhaven National Laboratory, Cornell University, Harvard (Prof. Subir Sachdev and Research Associate Mohammad Hamidian), and other institutions, have characterized a key arrangement of electrons in a high-temperature superconductor, a material that can conduct electricity with almost no energy loss without being ultra-chilled. The material is a member of a family of copper-oxygen-based superconducting compounds - the cuprates - that are prime candidates for numerous potential high-impact applications, including extremely efficient electricity generation, storage, and transmission across the nation's power grid.

The phenomenon they studied is known as an electron density wave. Unlike the other electrons in the material, which move about freely, the density wave is a periodic, fixed electron phase that seems to compete with and hinder the superconducting phase. Many researchers believe that the density wave is the key to unlocking the cuprates: if they can thoroughly understand the electron density wave, they say, they may be able to determine how to suppress or remove it to induce superconductivity, possibly even at room temperature. But to achieve this goal, they first must gain a thorough understanding of the causes of the electron density wave.

The current study is the first to identify the atomic-scale origins and influences that produce the density wave in cuprates.

Read more at: http://phys.org/news/2015-10-unraveling-complex-intertwined-electron-phases.html#jCp . Also read the original Nature Physics Letter: M.H. Hamidian, et al., "Atomic-scale electronic structure of the cuprate d-symmetry form factor density wave state," Nature Physics (2015) doi:10.1038/nphys3519.