Anisotropic superconductivity in the quasi-one-dimensional superconductor V${}_2$Ga${}_5$

Abstract

The intermetallic quasi-one-dimensional binary superconductor V${}_2$Ga${}_5$ was recently found to exhibit a topologically nontrivial normal state, making it a natural candidate for a topological superconductor (TSC). By combining dc-magnetization, nuclear magnetic resonance (NMR), and muon-spin rotation ({$\mu$SR) measurements on high-quality V${}_2$Ga${}_5$ single crystals, we investigate the electronic properties of its normal- and superconducting (SC) ground states. NMR measurements in the normal state indicate a strong anisotropy in both the line shifts and the relaxation rates. Such anisotropy persists also in the superconducting state, as shown by the magnetization- and $\mu$SR-spectroscopy results. In the latter case, data collected at different temperatures, pressures, and directions of the magnetic field evidence a fully-gapped, strongly anisotropic superconductivity. At the same time, hydrostatic pressure is shown to only lower the $T_c$ value, but not to change the superfluid density nor its temperature dependence. Lastly, we discuss the search for topological signatures in the normal state of V${}_2$Ga${}_5$, as well as a peak splitting in the FFT of the $\mu$SR spectrum, possibly related to an unconventional vortex lattice. Our results suggest that V${}_2$Ga${}_5$ is a novel system, whose anisotropy plays a key role in determining its unusual electronic properties.

14 pages, 11 figures, including Suppl. Information

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