[institut] Seminar Centra za fiziku čvrstog stanja i nove materijale

[Zoran Popovic]

Поштоване колегинице и колеге,
Дозволите ми да Вас подсетим на данашњи семинар у 13.00 у читаоници ИФ-а

Професор Ефтимиос Лиарокапис из Националног техничког универзитета у 
Атини одржаће семинар под насловом

"Lattice effects in high Tc superconductors”

Резиме предавања дат је у даљем тексту.
Позивамо Вас да дођете на наведено предавање.
Срдачан поздрав
Зоран В. Поповић


"Lattice effects in high Tc superconductors”

Efthymios Liarokapis

Department of Physics, National Technical University of Athens

Abstract

Since the discovery of high temperature superconductors (HTS) the role 
of lattice to the pairing mechanism was questioned due to the small 
isotope effect on the transition temperature (Tc). Subsequent 
measurements have found that isotope effect of Tc is large in underdoped 
cuprates and it exists in the magnetic penetration depth, the pseudogap 
temperature, and some other characteristic quantities. But many 
researchers believe in a purely electronic origin of the pair coupling 
and ignore any contribution of the lattice in the high Tc 
superconductivity. Therefore, even now the effect of lattice in the HTS 
coupling is unclear. Following the discovery of cuprates with the 
highest up to now Tc at ambient pressures (133K and 164K at high 
pressures), other compounds have been discovered with most recent the 
sulphur hydride with even higher Tc (203K) at ~90GPa. The isotope shift 
of this compound, consistent with BCS theory, points to an 
electron-phonon mechanism and shows that conventional coupling can 
induce very high Tc. In this presentation our experimental results will 
be presented that indicate the role of lattice in the HTS.

-- 
Institute of Physics Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
http://www.ipb.ac.rs/