Anomalous Landau level gaps near magnetic transitions in monolayer WSe$_2$

Fuente: arXiv
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Main Authors: Foutty, Benjamin A., Calvera, Vladimir, Han, Zhaoyu, Kometter, Carlos R., Liu, Song, Watanabe, Kenji, Taniguchi, Takashi, Hone, James C., Kivelson, Steven A., Feldman, Benjamin E.
Format: Preprint
Published: 2024
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author Foutty, Benjamin A.
Calvera, Vladimir
Han, Zhaoyu
Kometter, Carlos R.
Liu, Song
Watanabe, Kenji
Taniguchi, Takashi
Hone, James C.
Kivelson, Steven A.
Feldman, Benjamin E.
author_facet Foutty, Benjamin A.
Calvera, Vladimir
Han, Zhaoyu
Kometter, Carlos R.
Liu, Song
Watanabe, Kenji
Taniguchi, Takashi
Hone, James C.
Kivelson, Steven A.
Feldman, Benjamin E.
contents First-order phase transitions produce abrupt changes to the character of both ground and excited electronic states. Here we conduct electronic compressibility measurements to map the spin phase diagram and Landau level (LL) energies of monolayer WSe$_2$ in a magnetic field. We resolve a sequence of first-order phase transitions between completely spin-polarized LLs and states with LLs of both spins. Unexpectedly, the LL gaps are roughly constant over a wide range of magnetic fields below the transitions, which we show reflects a preference for opposite spin excitations of the spin-polarized ground state. These transitions also extend into compressible regimes, with a sawtooth boundary between full and partial spin polarization. We link these observations to the important influence of LL filling on the exchange energy beyond a smooth density-dependent contribution. Our results show that WSe$_2$ realizes a unique hierarchy of energy scales where such effects induce re-entrant magnetic phase transitions tuned by density and magnetic field.
format Preprint
id arxiv_https___arxiv_org_abs_2401_01486
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Anomalous Landau level gaps near magnetic transitions in monolayer WSe$_2$
Foutty, Benjamin A.
Calvera, Vladimir
Han, Zhaoyu
Kometter, Carlos R.
Liu, Song
Watanabe, Kenji
Taniguchi, Takashi
Hone, James C.
Kivelson, Steven A.
Feldman, Benjamin E.
Mesoscale and Nanoscale Physics
First-order phase transitions produce abrupt changes to the character of both ground and excited electronic states. Here we conduct electronic compressibility measurements to map the spin phase diagram and Landau level (LL) energies of monolayer WSe$_2$ in a magnetic field. We resolve a sequence of first-order phase transitions between completely spin-polarized LLs and states with LLs of both spins. Unexpectedly, the LL gaps are roughly constant over a wide range of magnetic fields below the transitions, which we show reflects a preference for opposite spin excitations of the spin-polarized ground state. These transitions also extend into compressible regimes, with a sawtooth boundary between full and partial spin polarization. We link these observations to the important influence of LL filling on the exchange energy beyond a smooth density-dependent contribution. Our results show that WSe$_2$ realizes a unique hierarchy of energy scales where such effects induce re-entrant magnetic phase transitions tuned by density and magnetic field.
title Anomalous Landau level gaps near magnetic transitions in monolayer WSe$_2$
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2401.01486