Magnetotransport across Weyl semimetal grain boundaries

Abstract

A clean interface between two Weyl semimetals features a universal, field-linear tunnel magnetoconductance of $(e^2/h)N_{\mathrm{ho}}$ per magnetic flux quantum, where $N_{\mathrm{ho}}$ is the number of chirality-preserving topological interface Fermi arcs. In this work we show that the linearity of the magnetoconductance is robust with to interface disorder. The slope of the magnetoconductance changes at a characteristic field strength $B_{\mathrm{arc}}$ -- the field strength for which the time taken to traverse the Fermi arc due to the Lorentz force is equal to the mean inter-arc scattering time. For fields much larger than $B_{\mathrm{arc}}$, the magnetoconductance is unaffected by disorder. For fields much smaller than $B_{\mathrm{arc}}$, the slope is no longer determined by $N_{\mathrm{ho}}$ but by the simple fraction $N_{\mathrm{L}}{N}_{\mathrm{R}}/(N_{\mathrm{L}}+N_{\mathrm{R}})$, where $N_{\mathrm{L}}$ and $N_{\mathrm{R}}$ are the numbers of Weyl-node pairs in the left and right Weyl semimetal, respectively. We also consider the effect of spatially correlated disorder potentials, where we find that $B_{\mathrm{arc}}$ decreases exponentially with increasing correlation length. Our results provide a possible explanation for the recently observed robustness of the negative linear magnetoresistance in grained Weyl semimetals.

8+3 pages, 6 figures

References in corpus (9)

• Quantized Transport in Graphene p-n Junctions in Magnetic Field
• Surface conduction and reduced electrical resistivity in ultrathin noncrystalline NbP semimetal
• Fermi arc reconstruction at the interface of twisted Weyl semimetals
• Robust negative longitudinal magnetoresistance and spin-orbit torque in sputtered Pt3Sn topological semimetal
• Surface-dominated conductance scaling in Weyl semimetal NbAs
• Atomically Sharp Internal Interface in a Chiral Weyl Semimetal Nanowire
• Fermi-arc metals
• Magnetic Breakdown and Chiral Magnetic Effect at Weyl-Semimetal Tunnel Junctions
• Quantum Oscillation Signatures of Fermi Arcs in Tunnel Magnetoconductance