Electronic state of superconductivity in line nodal material CaSb2 under pressure up to 4.2 GPa

Abstract

We report the results of resistance measurements under pressure up to $4.2\,\mathrm{GPa}$ on single-crystalline $\mathrm{CaSb}_2$ , which shows the maximum of superconducting transition temperature $T_\mathrm{c}$ at $3.1\,\mathrm{GPa}$. At room temperature, $R(P)$ shows a subtle anomaly at $3.1\,\mathrm{GPa}$. However, Bloch-Grüneisen analysis of $R(T)$ indicates that the electronic state does not change significantly across $3.1\,\mathrm{GPa}$.

Figures (2)

• Figure 1: (Color online) Temperature dependence of resistance under various pressures for (a) the sample1 and (b) the sample2. The arrows in the insets represent $T_{\mathrm{c}}$ determined from the onset of superconductivity. (c) Pressure dependence of $T_{\mathrm{c}}$ of $\mathrm{CaSb}_2$. The dashed lines are guides to the eye taken from ref. kitagawa2021. (d) Pressure dependence of the resistance normalized at ambient pressure.
• Figure 2: (Color online) (a) Temperature dependence of resistance of the sample2 at $3.0 \,\mathrm{GPa}$. Solid line is experimental data, dashed line is fitting line with eq.(3) using the normal-state data up to $100 \,\mathrm{K}$. (b)(c) Pressure dependence of the fitting parameters, $A$, $\theta_R$. Closed symbols mean that fitting range is up to $50\,\mathrm{K}$. Open symbols mean up to $100\,\mathrm{K}$.