The study marks the first time researchers have been able to directly measure when electrons in a super conductor behave as independent well-defined particles, and when they evolve into ill-defined many-body entities.
"We've never been able to directly quantify the nature of electron behaviour within these materials across the entire phase diagram--the transition from non-superconducting to superconducting behaviour," says Associate Professor Andrea Damascelli, Canada Research Chair in Electronic Structure of Solids with the Department of Physics and Astronomy.
"A combination of advanced spectroscopic techniques, and access to very pure cuprate crystals produced at UBC have allowed us to measure what's going on below the surface of a high-temperature superconducting material through the entire progression of different phases."
The paper, the first out of the newly created Quantum Matter Institute at UBC in collaboration with researchers from the Advanced Light Source at Lawrence Berkeley National Laboratory, was published this week in the journal Nature Physics.
Cuprates normally act as insulators but become superconductors when electrons are removed--a process known as 'doping' holes into the material. Physicists consider a material optimally doped when it achieves superconductivity at the highest, most accessible temperature. A material is 'underdoped' when its level of doping is less than the level that maximizes the superconducting temperature.
A central debate in the field has focused on whether high-temperature superconductivity--the ability to conduct electricity without resistance at record high temperatures--emerges from a fluid of individual Fermi liquid quasiparticles (the electron-like entities ‘dressed’ by the interactions with their surrounding that give rise to conventional low-temperature superconductivity), or is instead a property connected to the physics of ‘strongly-correlated’ Mott insulators, in which many-body electron behavior wipes quasiparticles completely out of existence.
Damascelli's team was able to measure a rapid loss of quasiparticle integrity in the material's electron behavior upon entering the cuprates' underdoped phase. "This implies that some very important concepts of Fermi liquid models breakdown entering this phase, and that we'll have to look in other theoretical directions to explain superconductivity."
UBC is world renowned for research excellence in quantum materials, and announced the establishment of the Max Planck-UBC Quantum Materials Center last week and the creation of a dedicated Quantum Matter Institute last May.Read the Nature Physics Paper
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24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
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In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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