$\require{mhchem}$Misfit phase $\ce{(BiSe)_{$1.10$}NbSe2}$ as the origin of superconductivity in nobium-doped bismuth selenide

Abstract

$\require{mhchem}$Topological superconductivity is of great contemporary interest and has been proposed in doped $\ce{Bi2Se3}$ in which electron-donating atoms such as Cu, Sr or Nb have been intercalated into the $\ce{Bi2Se3}$ structure. For $\ce{Nb_{x}Bi2Se3}$, with ${\text{T}}_{\text{c}}\sim 3\text{K}$, it is assumed in the literature that Nb is inserted in the van der Waals gap. However, in this work an alternative origin for the superconductivity in Nb-doped $\ce{Bi2Se3}$ is established. In contrast to previous reports, it is deduced that Nb intercalation in $\ce{Bi2Se3}$ does not take place. Instead, the superconducting behaviour in samples of nominal composition $\ce{Nb_{x}Bi2Se3}$ results from the $\ce{(BiSe)_{$1.10$}NbSe2}$ misfit phase that is present in the sample as an impurity phase for small $x$ ($0.01\le x\le 0.10$) and as a main phase for large $x$ ($x=0.50$). The structure of this misfit phase is studied in detail using a combination of X-ray diffraction and transmission electron microscopy techniques.

References in corpus (5)

• Realization of an acoustic third-order topological insulator
• Nematic superconductivity in doped Bi2Se3 topological superconductors
• Superconductivity by Sr Intercalation in Layered Topological Insulator Bi2Se3
• Growth and anisotropy evaluation of NbBiCh${}_3$ (Ch = S, Se) misfit-layered superconducting single crystals
• Chemical Migration and Dipole Formation at van der Waals Interfaces between Magnetic Transition Metal Chalcogenides and Topological Insulators

Cited by in corpus (3)

• One-dimensional electronic states in a natural misfit structure
• Anisotropic Upper Critical Field, Seebeck and Nernst Coefficient in Nb0.20Bi2Se3 Topological Superconductor
• Sensitivity of superconducting states to the impurity location in layered materials