Physics

Determining the properties and morphology of buried layers and interfaces is an important area in solid-state science with synchrotrons being the meeting ground of state-of-the-art theory and high-precision experimental results. The wolrd's first dedictaed synchrotron was used to help study giant magneto-resistance (GMR), which is now used in billions of electronic devices worldwide.

Superconductor discovery an advancement for technology

Canadian Light Source, Saskatoon, Canada

Scientists have discovered a universal behavior in copper-based (cuprate) superconductors, paving the way for a crucial advancement in understanding and development of these fascinating materials that will have implications on everything from producing smaller, more efficient MRI machines to making better power lines.

The international team found that the so-called charge-density-waves – spatial modulations of the electronic density in a crystal – are the same in all cuprate compounds.

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Emerging research suggests a new paradigm for "unconventional superconductors

An example of superconductivity.
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An example of superconductivity.

CHESS, Cornell University, USA

Superconductivity in so-called unconventional superconductors, for example copper-oxide, iron-arsenide and iron-selenide high-temperature superconductors, is nearly always found in the vicinity of another ordered state, such as antiferromagnetism, charge density wave (CDW), or stripe order. This suggests a fundamental connection between superconductivity and fluctuations in some other order parameter.

A team of scientists has reported that emergence of superconductivity in the CDW system TiSe2 coincides with a quantum critical point (QCP) at which the CDW phase transition temperature goes to zero, suggesting TiSe2 exemplifies the universal phenomenon of superconductivity emerging near suppression of an ordered state.

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First laser-like X-ray light from a solid

The incoming laser light (depicted in green) excites the atoms in the silicon crystal to produce its own laser puls with a slightly longer wavelength (depicted in red).
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The incoming laser light (depicted in green) excites the atoms in the silicon crystal to produce its own laser puls with a slightly longer wavelength (depicted in red).

FLASH, DESY, Hamburg, Germany

Researchers have for the first time created an X-ray laser based on a solid. The method developed at DESY's free-electron laser FLASH opens up new avenues of investigation in materials research, as reported by the team of Prof. Alexander Föhlisch of the Helmholtz Zentrum Berlin (HZB) in the British scientific journal "Nature." "This technology makes it possible to analyse sensitive samples that otherwise are quickly destroyed by intense X-ray light," notes co-author Prof. Wilfried Wurth of the University of Hamburg and the Hamburg Center for Free-Electron Laser Science (CFEL), a collaborative effort by DESY, the Max Planck Society and the University of Hamburg.

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One pulse good, two pulses better

Elettra Sincrotrone Trieste, Italy

Two-pulse two-colour free-electron laser provide a self-standing source for pump-probe experiments.

Understanding the exotic properties of matter driven to extreme non-equilibrium states by interaction with very intense VUV/X rays, has become possible with the advent of ultrabright free electron lasers (FEL). Development of different photon correlation schemes, with temporal and spatial resolution determined only by the FEL pulse duration and wavelength, are key steps towards accessing ultra-fast dynamic phenomena.

The dynamics is initiated by the first “pump” pulse, which generates carriers at time scales shorter than carrier diffusion and electron-phonon scattering. The evolution of the transient states is then monitored by a second “probe” pulse arriving at variable and defined time delay. Tuning the pulse wavelengths to atomic resonances opens an unprecedented opportunity to add selectively elemental sensitivity to the mesurement, which is essential for exploring ultrafast processes in morphologically complex multicomponent materials.

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