arXiv subjects

A. Kool

Publications and source records attributed to A. Kool.

2 recordsLinked to original sources

arXiv2026

$H$-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.

cond-mat.str-el↗

arXiv2024

Uniaxial strain effects on the Fermi surface and quantum mobility of the Dirac nodal-line semimetal ZrSiS

ZrSiS has been identified as an exemplary Dirac nodal-line semimetal, in which the Dirac band crossings extend along a closed loop in momentum space. Recently, the topology of the Fermi surface of ZrSiS was uncovered in great detail by quantum oscillation studies. For a magnetic field along the tetragonal $c$ axis, a rich frequency spectrum was observed stemming from the principal electron and hole pockets, and multiple magnetic breakdown orbits. In this work we use uniaxial strain as a tuning parameter for the Fermi surface and the low energy excitations. We measure the magnetoresistance of a single crystal under tensile (up to 0.34 %) and compressive (up to -0.28 %) strain exerted along the $a$ axis and in magnetic fields up to 30 T. We observe a systematic weakening of the peak structure in the Shubnikov-de Haas frequency spectrum upon changing from compressive to tensile strain. This effect may be explained by a decrease in the effective quantum mobility upon decreasing the $c/a$ ratio, which is corroborated by a concurrent increase in the Dingle temperature.

cond-mat.mtrl-sci↗