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We report the effect of remote surface optical (RSO) phonon scattering on carrier mobility in monolayer graphene gated by ferroelectric oxide. We fabricate monolayer graphene transistors back-gated by epitaxial (001) Ba0.6Sr0.4TiO3 films, with field effect mobility up to 23 000 cm2 V−1 s−1 achieved. Switching ferroelectric polarization induces nonvolatile modulation of resistance and quantum Hall effect in graphene at low temperatures. Ellipsometry spectroscopy studies reveal four pairs of optical phonon modes in Ba0.6Sr0.4TiO3, from which we extract RSO phonon frequencies. The temperature dependence of resistivity in graphene can be well accounted for by considering the scattering from the intrinsic longitudinal acoustic phonon and the RSO phonon, with the latter dominated by the mode at 35.8 meV. Our study reveals the room temperature mobility limit of ferroelectric-gated graphene transistors imposed by RSO phonon scattering.
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Room-temperature modulation of microwave conductivity in ferroelectric-gated correlated oxides
We report the nonvolatile modulation of microwave conductivity in ferroelectric PbZr0.2Ti0.8O3-gated ultrathin LaNiO3/La0.67Sr0.33MnO3 correlated oxide channel visualized by microwave impedance microscopy. Polarization switching is obtained by applying a tip bias above the coercive voltage of the ferroelectric layer. The microwave conductivity of the correlated channel underneath the up- and down-polarized domains has been quantified by finite-element analysis of the tip-sample admittance. At room temperature, a resistance on/off ratio above 100 between the two polarization states is sustained at frequencies up to 1 GHz, which starts to drop at higher frequencies. The frequence-dependence suggests that the conductance modulation originates from ferroelectric field-effect control of carrier density. The modulation is nonvolatile, remaining stable after 6 months of domain writing. Our work is significant for potential applications of oxide-based ferroelectric field-effect transistors in high-frequency nanoelectronics and spintronics.
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- PAR ID:
- 10567189
- Publisher / Repository:
- Institute of Physics
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 125
- Issue:
- 18
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0231424
