Emergent Magnetism at the AlO<sub>x</sub>/KTaO<sub>3</sub> Interface Probed with mK Transport Measurements
ORAL
Abstract
Here we report signatures of emergent magnetism measured through electrical transport on the two-dimensional electron gas (2DEG) hosted at the interface between AlOx and KTaO3 (KTO). In samples fabricated to suppress superconductivity we see a gate voltage tuned magnetism characterized by a zero-field transverse voltage that is strongly asymmetric with respect to an applied perpendicular magnetic field and becomes strongly hysteretic at the lowest measured temperatures. These results are discussed for three different crystal terminations of KTO, and interpreted based on the complex spin texture of the KTO surface. Density functional theory results confirm that oxygen vacancies result in a net spin polarization leading to a finite Berry curvature, explaining the transverse voltage and the striking hysteretic behavior. We also discuss compelling related results measured at higher temperatures in non-local differential resistance.
[1] Krantz et al. arxiv.org/abs/2209.10534 (2022)
[2] Krantz and Chandrasekhar, In Preparation. (2022)
[1] Krantz et al. arxiv.org/abs/2209.10534 (2022)
[2] Krantz and Chandrasekhar, In Preparation. (2022)
*This work was supported by the U.S. Department of Energy, Basic Energy Sciences, under Award No. DE-FG02-06ER46346. This work also made use of the NUFAB facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-1720139). Additional equipment support was provided by DURIP grant W911NF-20-1-0066.
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Publication: Emergent Magnetism and Intrinsic Anomalous Hall Effect in KTaO3 Two-Dimensional Electron Gases, Krantz et al. https://arxiv.org/abs/2209.10534, Nonlocal Differential Resistance in AlOx/KTaO3 Heterostructures, Krantz and Chandrasekhar, In Preparation, 2022
Presenters
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Patrick W Krantz
- Northwestern University