Wydarzenia

Seminarium Międzynarodowego Laboratorium Silnych Pól Magnetycznych i Niskich Temperatur PAN

ARPES view on electronic structure of superconductors

prof Alexander Kordyuk

Institute of Metal Physics, Kyiv, Ukraine

Electronic structure of crystals, the distribution of electron density of states in energy-momentum space, which is easily seen by angle resolved photoemission spectroscopy (ARPES), defines virtually all the electronic properties of those crystals and is often self-sufficient to understand its evolution over electronic phase transitions [1]. This talk is an introduction to ARPES on high temperature superconductors: cuprates (Cu-SC) [2] and iron based compounds (Fe-SC) [3], with focus on resent study of temperature evolution of electronic band structure in these materials and its possible relation to superconductivity.

ARPES studies suggest the phase diagram of Cu-SC where the SDW and superconductivity competes for the phase space [2]. On the other hand, the SDW-reconstructed Cu-SC share with Fe-SC the empirical correlation between the Tc maximum and the proximity of the Fermi surface to the topological Lifshitz transition [3]. This suggests that the aforementioned Fermi surface criticality could be a general mechanism for high temperature superconductivity [2]. Moreover, it seems that the electronic band structure of Fe-SC strongly evolves with temperature namely towards this criticality. Possible mechanisms of this evolution are also discussed.

[1] A. A. Kordyuk, Low Temp. Phys. 40, 286 (2014).
[2] A. A. Kordyuk, Low Temp. Phys. 41, 319 (2015).
[3] A. A. Kordyuk, Low Temp. Phys. 38, 888 (2012).