Probing the quantum metric of 3D topological insulators

Fuente: arXiv
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Autori principali: Sala, Giacomo, Longo, Emanuele, Mercaldo, Maria Teresa, Gariglio, Stefano, Cuoco, Mario, Mantovan, Roberto, Ortix, Carmine, Caviglia, Andrea D.
Natura: Preprint
Pubblicazione: 2025
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author Sala, Giacomo
Longo, Emanuele
Mercaldo, Maria Teresa
Gariglio, Stefano
Cuoco, Mario
Mantovan, Roberto
Ortix, Carmine
Caviglia, Andrea D.
author_facet Sala, Giacomo
Longo, Emanuele
Mercaldo, Maria Teresa
Gariglio, Stefano
Cuoco, Mario
Mantovan, Roberto
Ortix, Carmine
Caviglia, Andrea D.
contents The surface states of 3D topological insulators possess geometric structures that imprint distinctive signatures on electronic transport. A prime example is the Berry curvature, which controls, for instance, electric frequency doubling via its higher order moments. In addition to the Berry curvature, topological surface states are expected to exhibit a nontrivial quantum metric, which plays a key role in governing nonlinear magnetotransport. However, its manifestation has yet to be experimentally observed and controlled in 3D topological insulators. Here, we provide evidence for a nonlinear response activated by the quantum metric of the topological surface states of Sb$_2$Te$_3$. We measure a time-reversal odd, nonlinear magnetoresistance that is independent from the temperature and the scattering time below 30 K, and is thus of intrinsic geometrical origin. This quantum metric magnetoresistance can be controlled by tuning the contributions of the top and bottom topological surface states by voltage gating. Our measurements thus demonstrate the existence and tunability of quantum geometry-induced transport in topological phases of matter and provide strategies for designing novel functionalities in topological devices.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17135
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing the quantum metric of 3D topological insulators
Sala, Giacomo
Longo, Emanuele
Mercaldo, Maria Teresa
Gariglio, Stefano
Cuoco, Mario
Mantovan, Roberto
Ortix, Carmine
Caviglia, Andrea D.
Mesoscale and Nanoscale Physics
Materials Science
The surface states of 3D topological insulators possess geometric structures that imprint distinctive signatures on electronic transport. A prime example is the Berry curvature, which controls, for instance, electric frequency doubling via its higher order moments. In addition to the Berry curvature, topological surface states are expected to exhibit a nontrivial quantum metric, which plays a key role in governing nonlinear magnetotransport. However, its manifestation has yet to be experimentally observed and controlled in 3D topological insulators. Here, we provide evidence for a nonlinear response activated by the quantum metric of the topological surface states of Sb$_2$Te$_3$. We measure a time-reversal odd, nonlinear magnetoresistance that is independent from the temperature and the scattering time below 30 K, and is thus of intrinsic geometrical origin. This quantum metric magnetoresistance can be controlled by tuning the contributions of the top and bottom topological surface states by voltage gating. Our measurements thus demonstrate the existence and tunability of quantum geometry-induced transport in topological phases of matter and provide strategies for designing novel functionalities in topological devices.
title Probing the quantum metric of 3D topological insulators
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2509.17135