Superconductivity in Cu Co-Doped Sr x Bi 2 Se 3 Single Crystals

• Published in: Materials 2019-11, Vol.12 (23)
• Main Authors: Kuntsevich, Aleksandr Yu, Martovitskii, Victor P, Rybalchenko, George V, Selivanov, Yuri G, Bannikov, Mikhail I, Sobolevskiy, Oleg A, Chigevskii, Evgenii G
• Format: Article
• Language: English
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12233899

In this study, we grew Cu co-doped single crystals of a topological superconductor candidate Sr x Bi 2 Se 3 , and studied their structural and transport properties. We reveal that the addition of even as small an amount of Cu co-dopant as 0.6 atomic %, completely suppresses superconductivity in Sr x Bi 2 Se 3 . Critical temperature (∼2.7 K) is rather robust with respect to co-doping. We show that Cu systematically increases the electron density and lattice parameters and . Our results demonstrate that superconductivity in Sr x Bi 2 Se 3 -based materials is induced by significantly lower Sr doping level x < 0.02 than commonly accepted x ∼ 0.06 , and it strongly depends on the specific arrangement of Sr atoms in the host matrix. The critical temperature in superconductive Sr-doped Bi 2 Se 3 is shown to be insensitive to carrier density.