Fermi surface mapping of the kagome superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>RbV</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Sb</mml:mi><mml:mn>5</mml:mn></mml:msub></mml:math> using de Haas-van Alphen oscillations
Keshav Shrestha, Mengzhu Shi, Thinh Nguyen, Duncan Miertschin, Kaibao Fan, Liangzi Deng, David Graf, Xianhui Chen, C. W. Chu
Abstract
We present the results from torque magnetometry studies of the kagome superconductor ${\mathrm{RbV}}_{3}{\mathrm{Sb}}_{5}$ under applied fields up to 45 T and temperatures down to liquid $^{3}\mathrm{He}$ temperature (0.32 K). The torque signal shows clear de Haas--van Alphen (dHvA) oscillations with eight distinct frequencies ranging from $\ensuremath{\approx}150$ to 3000 T. Among these, five are above 500 T. Angle-dependent measurement of dHvA oscillations shows that all frequencies follow 1/$\mathrm{cos}\ensuremath{\theta}$ dependence, where $\ensuremath{\theta}$ is the tilt angle with respect to the applied field direction, and the oscillations disappear above $\ensuremath{\theta}$ = ${60}^{\ensuremath{\circ}}$, which confirms that the Fermi surfaces corresponding to these frequencies are two dimensional. The Berry phase ($\ensuremath{\phi}$), calculated by constructing a Landau level fan diagram, is found to be $\ensuremath{\approx}\ensuremath{\pi}$, which strongly supports the nontrivial topology of ${\mathrm{RbV}}_{3}{\mathrm{Sb}}_{5}$. Using the Lifshitz-Kosevich formula, we estimate the effective mass (${m}^{*}$) of charge carriers in ${\mathrm{RbV}}_{3}{\mathrm{Sb}}_{5}$, and it is found to be heavier ($\ensuremath{\approx}0.7{m}_{o}$, where ${m}_{o}$ is the free electron mass) than that for other topological insulators. The findings of high frequencies up to 3000 T in ${\mathrm{RbV}}_{3}{\mathrm{Sb}}_{5}$ have not been reported previously, and the results regarding the Fermi surface of ${\mathrm{RbV}}_{3}{\mathrm{Sb}}_{5}$ are crucial for understanding the charge density wave order, superconductivity, and nontrivial topology in $A{\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ ($A$ = K, Rb, and Cs), as well as the interplay among them.