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08.10.2014

Ultra-fast laser has helped to change the properties of solid materials

Scientists from the United States, South Korea and Japan have used ultrafast (femtosecond) laser for rapid change tracking self-energy electrons and their interactions in a superconductor. Results of their research the authors published in the Nature Communications magazine, and briefly with them can be found at the National Laboratory Lawrence Berkeley (USA). 

Scientists have used photoelectron spectroscopy with angular and temporal resolution for the direct measurement of ultrafast electron self-energy changes during irradiation of high-temperature superconductors based on cuprates. Superconductors - a special material that below the critical temperature have zero electrical resistance. 

In the case of high conductivity such a situation can be achieved at minus 240 degrees Celsius. Cuprates Bi2212, used by scientists, are compounds of bismuth, strontium, calcium and copper oxide and are a common material for high-temperature superconductivity research. Scientists have found that below the critical temperature ultrafast excitations of such material cause synchronous decline in the self-energy electrons and the width of the superconducting gap. Above the critical temperature ultrafast excitation had no marked effect on the interaction of electrons and bosons (atomic nuclei with an even number of protons and neutrons).Ultrafast spectroscopy is a promising method for the study of the quantum properties of materials. Still change issues in the electron self-energy of many superconducting systems have not received wide coverage in the work of scientists. 

Experts believe that the technique of ultrafast excitation shown by them, allow to control the properties of materials with light, and can be used in studies of correlation effects in superconducting solids.

Source: Lenta.ru

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