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NEW INSIGHTS INTO HIGH-

CRITICAL-TEMPERATURE COPPER-

BASED SUPERCONDUCTORS

Teams from the Politecnico di Milano, Chalmers underlying high-temperature superconductivity.”
University of Technology Gothenburg, and
Riccardo Arpaia, a researcher at the Chalmers
Sapienza University of Rome have recently
University Department of Microtechnology,
conducted experiments with high-critical-
elaborates further on the theory:
temperature copper-based superconductors
and made some remarkable discoveries. “ A quantum critical point identifies specific
conditions where a material undergoes a sudden
In particular, even above their critical temperature,
change in its properties due solely to quantum
these materials have been found to behave as
effects. Just like ice melts and becomes liquid
‘strange metals’ with their electrical resistance
at zero degrees Celsius due to microscopic
being observed to vary with temperature in a
temperature effects, cuprates turn into a ‘strange
unique manner, and a ‘quantum critical point has
metal’ because of quantum charge fluctuations”.
been associated with this ‘strange metal’ phase.
Giacomo Ghiringhelli, Professor at the Politecnico
The breakthrough arose following X-ray scattering
di Milano Department of Physics and co-ordinator
experiments conducted at the European
of the research, adds:
Synchotron ESRF and the British Synchotron DLS
which revealed charge density fluctuations in “ This is the result of more than five years of
cuprates that affect their electrical resistance, work. We used a technique, called RIXS, largely
contributing to their ‘strange’ nature. A key aspect developed by us at the Politecnico di Milano.
of the research was to determine the charge Thanks to new measurement campaigns and
carrier density at which these fluctuations reach to new data analysis methods, we were able to
their minimum energy, that is the ‘quantum prove the existence of the quantum critical point.
critical point’. A better understanding of cuprates will guide the
design of even better materials, with higher critical
Sergio Caprara of the Sapienza University of
temperatures, and therefore easier to exploit in
Rome’s Department of Physics, who proposed the
tomorrow’s technologies.”
theory, states:
[ Reference: West, P., ‘ A Step towards more
“This discovery represents an important
sustainable Superconductor Applications’,
advancement in understanding not only the
Electronic Specifier, 11th. December 2023 ]
anomalous properties of the metallic state of
cuprates, but also the still obscure mechanisms

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