Lisa Buchauer, LPEM

Jeudi 18 Septembre 2014, 14h
Amphi Holweck, Esc C, 1ème etage

Superconductivity and Fermi surface in Tl:PbTe

Lisa Buchauer
LPEM

Lead telluride (PbTe) is a narrow-gap semiconductor which exhibits metallic character and a clear Fermi surface even in the absence of controlled doping. The Fermi surface of p-type PbTe for carrier concentrations below 10^19 holes per cm^3 is known to consist of four ellipsoidal pockets at the L-points of the fcc-Brillouin zone. Furthermore, upon doping with thallium (Tl) PbTe becomes a superconductor above a critical carrier concentration of p=5*10^19 cm^-3, corresponding to a critical doping-level of x(Tl)=0.4%.
In this work, the evolution of the Fermi surface of Tl-doped PbTe for p> 10^19 cm^-3 was explored in order to look for a possible link between emerging superconductivity and a change in Fermi surface topology. Paying particular attention to the critical doping range around x(Tl)=0.4%, a series of seven samples with carrier concentrations between 1.5*10^19 cm^-3 and 9*10^19 cm^-3 was analysed using the Shubnikov-de Haas effect (quantum oscillations in resistivity) as a probe.
Evidence was found that the emergence of a superconducting ground state at a critical carrier concentration is concomitant with the observation of an additional oscillation frequency which we attribute to a new set of twelve ellipsoidal Fermi surface pockets at the Sigma-points of the Brillouin-zone. This has implications for the mechanism of superconductivity in Tl:PbTe.

Haut de page



À lire aussi...

C. Bell, University of Bristol

Jeudi 05 June 2014, 14hAmphi Holweck, Esc C, 1ème etage Controlling 2D superconductivity and quantum oscillations in SrTiO3-based heterostructures (...) 

> Lire la suite...

R. L. Greene, Center for Nanophysics and Advanced Materials (CNAM), University of Maryland

Jeudi 03 July 2014, 14hAmphi Holweck, Esc C, 1ème etage Topological Surface States in the Kondo Insulator SmB6 ? R. L. GreeneCenter for (...) 

> Lire la suite...