Enhanced magnetoresistance in the binary semimetal NbAs2 due to improved crystal quality

We have observed an extremely large magnetoresistance exceeding 1.9 million at 1.7 K at 40 T for a single crystal of the binary semimetal ${\mathrm{NbAs}}_{2}$. The magnetoresistive behavior for this compound is quantitatively reproduced by a semiclassical two-carrier model in which the significant enhancement of magnetoresistance is attributed to the almost full compensation of the hole and electron densities $(0.994l{n}_{\mathrm{h}}/{n}_{\mathrm{e}}\ensuremath{\le}0.999)$ as well as the high mobility $(g6\ifmmode\times\else\texttimes\fi{}{10}^{5}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{2}/\mathrm{V}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{s})$. Our results indicate that binary semimetals with higher carrier densities have a great potential for exhibiting a further divergent increase in magnetoresistance merely through an improvement in crystal quality.