Curriculum VitaeCourses Taught, (most) Through 2021 Selected Research Talks, approx. dates Featured Research, viz. News&Views Recent Service: Research Organizations List of Presentations, through 22017
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The First Near-Room Temperature Superconductor
The Fermi surfaces in H3S indicate the nearby van Hove singularities that promote this simple compound the first metal hydride metal with a superconducting temperature Tc above 200 kelvin. Red circles indicate touching surfaces, red ellipses outline low velocity regions of intersecting surfaces. |
Description of the MnO Mott transition from insulator to metal at one million atmospheres pressure. We extended and applied the dynamical mean field theory method to obtain the magnetic and volume collapse transition. It was found that Hund's rule exchange processes are important for obtaining the correct transformation pressure. Moreover, residual magnetism was obtained from the calculation, in agreement with spectroscopic data. The figure provides the current knowledge on the pressure-temperature phase diagram of MnO. |
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In 2014 Eliashberg theory (carried out in China) predicted that hydrogen sulfide H3S would become a super-high temperature superconductor at the very high pressure of 1.6-2 million atmospheres. In 2005 Eremets' group in Germany measured and found superconductivity up to 203K at 1.6 million asmospheres, the same amazing result. One of our contributions has been to perform an ab initio molecular dynamics simulation of atomic vibrations of H3S at a temperature of 200 K and the experimental pressure. The hydrogen vibration amplitudes are very large; in a metal with normal (heavy) nuclei, the vibration would hardly be visible. Note: this video (click the title) may be slow to load. |
Superconductivity in compressed lithium approaches 20 kelvin.
Our group found that Fermi surface (left frame) hot spots
(red areas in right frame) are the key to strong electron-phonon coupling.
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