Checkerboard patterns of charge stripes in the two-gap superconductor ZrB12

作者：Nadezhda B. Bolotina, Olga N. Khrykina, Andrey N. Azarevich, N. Yu. Shitsevalova, Volodymyr B. Filipov, S. Yu. Gavrilkin, Kirill V. Mitsen, В. В. Воронов, Nikolay E. Sluchanko · 发表于：Physical review. B./Physical review. B · 年份：2022 · DOI：10.1103/physrevb.105.054511 · 被引用次数：14 · 研究领域：Iron-based superconductors research、Rare-earth and actinide compounds、Superconductivity in MgB2 and Alloys

Inhomogeneous superconductivity was studied in ${\mathrm{ZrB}}_{12}$ $({T}_{\mathrm{c}}\ensuremath{\approx}6\phantom{\rule{0.16em}{0ex}}\mathrm{K})$ using heat capacity and x-ray diffraction data. Evidence of two-band superconductivity with two branches of upper critical field ${\mathbf{H}}_{c2}({T}_{c})$ is obtained in a magnetic field applied along the [110] axis of the crystal. On the contrary, at H || [100], a single dependence $\mathbf{H}{c}_{2}({T}_{c})$ was observed. This finding is consistent with the checkerboard-type patterns observed on the difference Fourier maps of the electron density distribution. These patterns are compared to those for the weakly coupled superconductor ${\mathrm{LuB}}_{12}$, ${T}_{\mathrm{c}}$ of which is 15 times lower than that of ${\mathrm{ZrB}}_{12}$. The probable nature of the two-gap superconductivity in ${\mathrm{ZrB}}_{12}$ is discussed.