Synopsis: A clean slate

Scanning tunneling spectroscopy can take advantage of the high-quality surface of Fe1+δSe1-xTex to learn more about iron-based superconductivity.
Synopsis figure
Illustration: T. Kato et al., Phys. Rev. B (2009)

Scanning tunneling spectroscopy (STS) has played a pivotal role in the investigation of the normal and superconducting states of the cuprate high-temperature superconductors because it can probe electronic properties, such as the superconducting energy gap, with atomic resolution.

Since STS is a surface-sensitive probe, the success of the method depends crucially on the quality of the crystal surface. Cleaved crystals should expose a single, atomically smooth plane, ideally without any surface reconstruction. In a Rapid Communication appearing in Physical Review B, Takuya Kato and collaborators from the Universities of Tokyo and Tsukuba in Japan carry out an STS investigation of Fe1+δSe1-xTex , which is structurally the simplest of the newly discovered iron-based high-temperature superconductors. They observe an atomically resolved square crystal lattice with no surface reconstruction; in contrast, other iron-based superconductors such as LaFeAsO1-xFx and BaFe2As2 have complicated surface structures that depend on how they were prepared. Kato et al. also measure a spatially homogeneous superconducting gap in Fe1+δSe1-xTex, in sharp contrast to the gap inhomogeneity present in cuprate superconductors, adding to the list of differences between these two classes of materials.

Given that it has such a simple structure and a high-quality surface that lends itself to STM measurements, Fe1+δSe1-xTex may prove to be the model system for a significant breakthrough in understanding iron-based superconductivity. – Alex Klironomos


More Features »

Subject Areas


Previous Synopsis

Next Synopsis

Atomic and Molecular Physics

May cooler molecules prevail

Read More »

Related Articles

Synopsis: Superconductivity Model Misses Its Target

Synopsis: Superconductivity Model Misses Its Target

Researchers have added dopant atoms to a quantum spin liquid in an effort to make it superconduct, but the material upended theory by remaining an insulator. Read More »

Focus: Nobel Prize—Topological Phases of Matter
Condensed Matter Physics

Focus: Nobel Prize—Topological Phases of Matter

The 2016 Nobel Prize in Physics was awarded to theoretical physicists whose work established the role of topology in understanding exotic forms of matter. Read More »

Focus: Detecting Photons With a Thermometer

Focus: Detecting Photons With a Thermometer

A new technique detects as few as 200 microwave photons at a time by the heat they supply to an electrical circuit. Read More »

More Articles