Intrinsic negative magnetoresistance from the chiral anomaly of multifold fermions

Fuente: arXiv
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Autori principali: Balduini, F., Molinari, A., Rocchino, L., Hasse, V., Felser, C., Sousa, M., Zota, C., Schmid, H., Grushin, A. G., Gotsmann, B.
Natura: Preprint
Pubblicazione: 2024
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author Balduini, F.
Molinari, A.
Rocchino, L.
Hasse, V.
Felser, C.
Sousa, M.
Zota, C.
Schmid, H.
Grushin, A. G.
Gotsmann, B.
author_facet Balduini, F.
Molinari, A.
Rocchino, L.
Hasse, V.
Felser, C.
Sousa, M.
Zota, C.
Schmid, H.
Grushin, A. G.
Gotsmann, B.
contents The chiral anomaly, a hallmark of chiral spin-1/2 Weyl fermions, is an imbalance between left- and right-moving particles that underpins both high and low energy phenomena, including particle decay and negative longitudinal magnetoresistance in Weyl semimetals. The discovery that chiral crystals can host higher-spin generalizations of Weyl quasiparticles without high-energy counterparts, known as multifold fermions, raises the fundamental question of whether the chiral anomaly is a more general phenomenon. Answering this question requires materials with chiral quasiparticles within a sizable energy window around the Fermi level, that are unaffected by trivial extrinsic effects such as current jetting. Here we report the chiral anomaly of multifold fermions in CoSi, which features multifold bands within about 0.85 eV around the Fermi level. By excluding current jetting through the squeezing test, we measure an intrinsic, longitudinal negative magnetoresistance. We develop the semiclassical theory of magnetotransport of multifold fermions that shows that the negative magnetoresistance originates in their chiral anomaly, despite a sizable and detrimental orbital magnetic moment contribution, previously unaccounted for. A concomitant nonlinear Hall effect supports the multifold-fermion origin of magnetotransport. Our work confirms the chiral anomaly of higher-spin generalizations of Weyl fermions, currently inaccessible outside the solid-state.
format Preprint
id arxiv_https___arxiv_org_abs_2404_19424
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Intrinsic negative magnetoresistance from the chiral anomaly of multifold fermions
Balduini, F.
Molinari, A.
Rocchino, L.
Hasse, V.
Felser, C.
Sousa, M.
Zota, C.
Schmid, H.
Grushin, A. G.
Gotsmann, B.
Mesoscale and Nanoscale Physics
Other Condensed Matter
High Energy Physics - Phenomenology
The chiral anomaly, a hallmark of chiral spin-1/2 Weyl fermions, is an imbalance between left- and right-moving particles that underpins both high and low energy phenomena, including particle decay and negative longitudinal magnetoresistance in Weyl semimetals. The discovery that chiral crystals can host higher-spin generalizations of Weyl quasiparticles without high-energy counterparts, known as multifold fermions, raises the fundamental question of whether the chiral anomaly is a more general phenomenon. Answering this question requires materials with chiral quasiparticles within a sizable energy window around the Fermi level, that are unaffected by trivial extrinsic effects such as current jetting. Here we report the chiral anomaly of multifold fermions in CoSi, which features multifold bands within about 0.85 eV around the Fermi level. By excluding current jetting through the squeezing test, we measure an intrinsic, longitudinal negative magnetoresistance. We develop the semiclassical theory of magnetotransport of multifold fermions that shows that the negative magnetoresistance originates in their chiral anomaly, despite a sizable and detrimental orbital magnetic moment contribution, previously unaccounted for. A concomitant nonlinear Hall effect supports the multifold-fermion origin of magnetotransport. Our work confirms the chiral anomaly of higher-spin generalizations of Weyl fermions, currently inaccessible outside the solid-state.
title Intrinsic negative magnetoresistance from the chiral anomaly of multifold fermions
topic Mesoscale and Nanoscale Physics
Other Condensed Matter
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2404.19424