[institut] SCL Seminar: Jernej Mravlje, Monday, 26 December, 14:00

[Darko Tanaskovic]

Dear colleagues,

You are cordially invited to the SCL seminar of the Center for the Study 
of Complex Systems, which will be held on Monday, 26 December 2016 at 
14:00 in the library reading room “Dr. Dragan Popović" of the Institute 
of Physics Belgrade. The talk entitled

Correlated-electron transport in hcp-Fe under extreme conditions present 
in inner Earth Core

will be given by Dr. Jernej Mravlje ("Jozef Stefan" Institute, 
Ljubljana, Slovenia).

Abstract of the talk:

The Earth's magnetic field is essential for the life as it protects the 
ozone layer from the solar wind. The magnetic field exists due to the 
geodynamo mechanism which is driven by convective processes in the 
liquid iron external core. Sufficiently low thermal conductivity is 
essential for the existence of the convection. Recently it has been 
discovered that the electron-phonon interaction is less efficient than 
believed earlier [1] and that the thermal conductivity is about 5 times 
larger than assumed in geophysical models, which questions what ensures 
the stability of the geodynamo. Work [2] suggested electron-electron 
interactions could play an important role. It considered hcp-Fe, 
believed to be the main constituent of the Earth's inner core, under 300 
GPa and 6000K present there and found a non-Fermi liquid behavior and 
large resistivity of the same magnitude as the electron-phonon one. We 
repeated the same calculations more precisely [3] and found that the 
hcp-Fe behaves as a Fermi liquid and that the calculated resistivity is 
about 1/4th of the one found due to the electron-electron scattering due 
to numerical mistakes in [2], which led to retraction of the paper. We 
calculated also thermal conductivity. The effect of electron-electron 
scattering on thermal conductivity is due to a breakdown of 
Wiedemann-Franz law larger than the effect on electrical conductivity. 
The calculated thermal conductivity is 540W/mK which is similar to the 
one obtained from the electron-electron scattering 300W/mK [4], which 
suggests electron-electron scattering plays a non-negligible role in the 
dynamics of the Earth's core.

[1] M. Pozzo, C. Davies, D. Gubbins, and D. Alfe, Nature 485, 
355,(2012).
[2] P. Zhang, R.E. Cohen, and K. Haule, Nature 517, 605 (2015).
[3] L. V. Pourovskii, J. Mravlje, A. Georges, S.I. Simak, I. A. 
Abrikosov, arXiv:1603.02287 (2016)
[4] M. Pozzo, C. Davies, D. Gubbins, and D. Alfe, Earth and Planet. Sci. 
Lett.  393, 159 (2014).


Best regards,
Darko Tanasković