Séminaire/Seminar - Unusual transport and superconducting properties of oxygen deficient tungsten oxides - Alexander Shengelaya

Mardi 4 juillet 2023 11 h 15- 12 h 

IMPMC - Sorbonne Université - 4 place Jussieu - 75005 Paris - Barre 22-23, 4e étage, salle 401

Alexander Shengelaya - Department of Physics, Tbilisi State University, Tbilisi, Georgia, Andronikashvili Institute of Physics, Tbilisi State University, Tbilisi, Georgia

Abstract

Despite exciting developments in the field of superconductivity over a period of three decades, cuprates remain the only materials which exhibit superconductivity above the liquid nitrogen boiling temperature at ambient pressure. In this talk I will present results of our studies of oxygen deficient tungsten oxides WO_3-x (0<x<1). In the samples with composition close to WO_2.9 the signatures of superconductivity with the transition temperature T_c = 80 K were registered by means of magnetization measurements. After lithium intercalation the T_c further raised to 94 K [1]. The small superconducting volume fraction and the absence of transition in resistivity measurements indicate that the superconductivity is localized in small regions which do not percolate. Performed resistivity and magnetoresistance measurements show that WO_2.9 also has unconventional normal state properties, which can be understood by considering polaronic nature of charge carriers in this compound [2].

[1] A. Shengelaya, K. Conder, K. A. Müller, J. Supercond. Nov. Magn. 33, 301 (2020).

[2] A. Shengelaya, F. La Mattina, K. Conder, Condens. Matter 5, 63 (2020).