Superconductivity in Cu Co-Doped SrxBi2Se3 Single Crystals

Materials. 2019. Vol. 12. No. 23. P. 3899.

Kuntsevich A., Martovitskiy V., Rybalchenko G., Selivanov Y., Bannikov M., Sobolevskiy O., Chigevskii E.

In this study, we grew Cu co-doped single crystals of a topological superconductor candidate SrxBi2Se3, 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 SrxBi2Se3. 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 a and c. Our results demonstrate that superconductivity in SrxBi2Se3-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 Bi2Se3 is shown to be insensitive to carrier density.

Keywords: монокристаллы, single crystals, superconductivity, сверхпроводимость, рентгеновская дифракция, топологические изоляторы, кристаллическая структура, doping, topological superconductors, topological insulators, crystal structure, X-ray difraction, топологические сверхпроводники, допирование