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

TL;DR

This study reveals checkerboard charge stripe patterns and two-gap superconductivity in ZrB12, highlighting its unique inhomogeneous superconducting properties and comparing them to LuB12.

Contribution

It provides the first detailed analysis of checkerboard charge stripe patterns and two-gap superconductivity in ZrB12 using heat capacity and XRD data.

Findings

Evidence of two-band superconductivity with two Hc2(Tc) branches at H //[110]

Checkerboard charge stripe patterns identified in ZrB12

Comparison of charge stripe structures with LuB12

Abstract

Inhomogeneous superconductivity in the high quality single crystals of ZrB12 (Tc = 6 K) has been studied using the heat capacity and x-ray diffraction (XRD) data. Evidence of two-band superconductivity with two branches of upper critical field Hc2(Tc) is obtained in a magnetic field applied along the [110] axis of the crystal. On the contrary, at H //[100], the only dependence Hc2(Tc) is observed. This finding is supplemented with the checkerboard-type patterns of the charge stripes in ZrB12 deduced from the detailed analysis of XRD data. These patterns are compared to the structure of the charge stripes in the weakly bound superconductor LuB12, whose Tc is 15 times lower than that of ZrB12. Probable nature of the two-gap superconductivity in ZrB12 with strongly enhanced characteristics is discussed.