$H$-linear magnetoresistance in NbSe${}_2$ due to impeded cyclotron motion

Linear magnetoresistance (LMR) is a widespread phenomenon observed in a host of quantum materials ranging from semiconductor nanostructures to quantum critical and strange metals. While multiple scenarios to explain LMR have been proposed, a complete understanding of the phenomenon remains elusive. Indeed, it is highly likely that the origin of LMR depends on the specific electronic state. Here, we report a study of the impact of disorder on the form of the magnetoresistance of the prototypical charge-density-wave (CDW) compound 2$H$-NbSe${}_2$. The magnetoresistance is shown to exhibit strong qualitative and quantitative agreement with Boltzmann transport analysis incorporating impeded cyclotron motion (ICM). We identify the source of ICM in 2$H$-NbSe${}_2$ as strong scattering sinks where the CDW order connects the high temperature Fermi cylinders. Such unusual “hotspots” provide an explanation for the observed LMR as well as for the long-unexplained absence of quantum oscillations inside the charge ordered state in 2$H$-NbSe${}_2$. These findings provide strong evidence that ICM generates LMR in certain correlated metals.