Agenda

Prochain séminaire LANEF/Matériaux Quantiques :

Jeudi 16 mai 2024 à 14h00

Yann Alexanian (Université de Genève)

“ Doping and temperature evolution of the pseudogap state of bulk electron-doped Sr2IrO4 seen by ARPES “

Pour accéder à ce séminaire :

Institut Néel CNRS, Bâtiment K, Salle Rémy Lemaire  (K223)

Résumé : Sr2IrO4 is a layered perovskite isostructural to the high Tc cuprate superconductor La2CuO4. The strong spin-orbit coupling of the 5d Ir4+ ions lifts the degeneracy of the t2g orbitals resulting in a single narrow half-filled band described by pseudospin Jeff=1/2 degrees of freedom. This promotes a Mott insultating ground state with antiferromagnetic order below 240 K despite the modest Coulomb interaction in the Ir 5d shell. These similarities with cuprates extend to the unusual metallic state of lightly electron doped Sr2IrO4 characterized by Fermi arcs and a pseudogap [1]. Based on this analogy, d-wave superconductivity was predicted [2] but to date no superconductivity was observed down to 100 mK.
In this presentation, I will show Angle Resolved Photoemission (ARPES) results on electron doped bulk crystals up to 10% doping, nearly two times higher than previously achieved. Our results show that nodal states become more coherent with increased doping while the antinodal pseudogap persists up to the highest doping. Following the temperature evolution of these features, we show that the pseudogap is reduced as the temperature increase, to become nearly undetectable at around 230 K for 10% doping [3].

References:
[1] A. De La Torre et al., Physical Review Letters, 115 (2015), 176402
[2] F. Wang and T. Senthil, Physical Review Letters, 106 (2011), 136402
[3] Y. Alexanian et al., in preparation

Les organisatrices :

Elsa Lhotel (elsa.lhotel@neel.cnrs.fr)
Florence Levy-Bertrand (florence.levy-bertrand@neel.cnrs.fr)