Magnetic-field-induced nonlocal transport in the topological semimetal ZrTe${}_5$

Nonlocal transport, which goes beyond the Ohm’s law, can be a key in understanding systems with topological order or edge states. Here we report an unusual nonlocal charge transport in the nodal-line semimetal ZrTe${}_5$ that occurs in the ultra-quantum limit driven by the magnetic field applied along the $a$-axis. Surprisingly, the observed decay length of the nonlocality exceeds 100 $\mu$m and it increases linearly with the sample width. This nonlocal transport is detected not only in the longitudinal configuration, but also in the transverse one as an unusual nonlocal Hall effect. Our findings demonstrate that the nonlocal response can offer unprecedented insights into topological quantum materials.