XXXVI Reunión Bienal de la Real Sociedad Española de Física

Looking for high Tc superconductivity in chromium pnictides and chalcogenides

Not scheduled

Aula Magna (Santiago de Compostela, Facultade de Química)

Description

Iron based high temperature superconductors were discovered in 2008 [1]. In these materials, superconductivity arises upon doping or applying pressure on an undoped compound with n=6 electrons in five d-orbitals. Unlike the cuprates, their close cousins, iron superconductors are not Mott insulators when undoped. These materials are correlated and that Hund’s coupling plays an important role on the correlations due to the multiorbital character of these systems [2]. Experimental and theoretical evidence shows that the strength of correlations increases with hole-doping the n=6 compounds, as the electronic filling approaches half-filling with n = 5 electrons. This evidence delineates a scenario in which the parent compound of iron superconductors is the half-filled system, in analogy to cuprate superconductors, with one electron in one orbital when undoped. In cuprates the superconductivity can be induced upon electron or hole doping. In this work we propose to search for high-Tc superconductivity and strong correlations in chromium pnictides and chalcogenides with n < 5 electrons. By means of ab-initio, slave spin and multi-orbital Random Phase Approximation calculations we analyse the strength of the correlations and the superconducting and magnetic instabilities in these systems with main focus on LaCrAsO. We find that electron-doped LaCrAsO is a strongly correlated system with competing magnetic interactions, being (π,π) antiferromagnetism and nodal d-wave pairing the most plausible magnetic and superconducting instabilities, respectively [3]. Acknowledgments Funding from Ministerio de Economía, Industria y Competitividad via grants No. FIS2012-33521, FIS2014-53218-P, FIS2015-64654-P, MAT2015-66888-C3-1-R. and from Fundación Ramón Areces is gratefully acknowledged. J.L. acknowledges the financial support of the Natural Science Foundation of China (11374186 and 51231007) and the China Scholarship Council. References [1] Y. Kamihara, T. Watanabe, M. Hirano and H. Hosono, J. Am. Chem. Soc. 130, 3296 (2008) [2] E. Bascones, B. Valenzuela, and M.J. Calderón, Comptes Rendus Physique 17, 36 (2016). [3] J.M. Pizarro, M.J. Calderón, J. Liu, M.C. Muñoz, and E. Bascones, Phys. Rev. B 95, 075115 (2017).