47 research outputs found
Effect of Sr-doping of LaMnO3 spacer on modulation-doped two-dimensional electron gases at oxide interfaces
Scavenging of oxygen vacancies at modulation-doped oxide interfaces: Evidence from oxygen isotope tracing
The introduction of manganite buffer layers, La7/8Sr1/8MnO3 (LSMO) in
particular, at the metallic interface between SrTiO3 (STO) and another band
insulator suppresses the carrier density of the interfacial two-dimensional
electron gas (2DEG) and improves significantly the electron mobility. However,
the mechanisms underlying the extreme mobility enhancement remain elusive.
Herein, we used 18O isotope exchanged SrTi18O3 as substrates to create 2DEG at
room temperature with and without the LSMO buffer layer. By mapping the oxygen
profile across the interface between STO18 and disordered LaAlO3 or
yttria-stabilized zirconia (YSZ), we provide unambiguous evidence that redox
reactions occur at oxide interfaces even grown at room temperature. Moreover,
the manganite buffer layer not only suppresses the carrier density but also
strongly suppresses the oxygen exchange dynamics of the STO substrate, which
likely prevents the reduction of STO during the formation of the 2DEG. The
underlying mechanism on the enhanced electron mobility at buffered oxide
interfaces is also discussed.Comment: to be apprear in PRMater, 201
Adaptive Rotated Convolution for Rotated Object Detection
Rotated object detection aims to identify and locate objects in images with
arbitrary orientation. In this scenario, the oriented directions of objects
vary considerably across different images, while multiple orientations of
objects exist within an image. This intrinsic characteristic makes it
challenging for standard backbone networks to extract high-quality features of
these arbitrarily orientated objects. In this paper, we present Adaptive
Rotated Convolution (ARC) module to handle the aforementioned challenges. In
our ARC module, the convolution kernels rotate adaptively to extract object
features with varying orientations in different images, and an efficient
conditional computation mechanism is introduced to accommodate the large
orientation variations of objects within an image. The two designs work
seamlessly in rotated object detection problem. Moreover, ARC can conveniently
serve as a plug-and-play module in various vision backbones to boost their
representation ability to detect oriented objects accurately. Experiments on
commonly used benchmarks (DOTA and HRSC2016) demonstrate that equipped with our
proposed ARC module in the backbone network, the performance of multiple
popular oriented object detectors is significantly improved (e.g. +3.03% mAP on
Rotated RetinaNet and +4.16% on CFA). Combined with the highly competitive
method Oriented R-CNN, the proposed approach achieves state-of-the-art
performance on the DOTA dataset with 81.77% mAP
Tuning the ground state of polar LaAlO<sub>3</sub>/SrTiO<sub>3</sub> interface by an electron sink
Diluted Oxide Interfaces with Tunable Ground States
The metallic interface between two oxide insulators, such as LaAlO3/SrTiO3
(LAO/STO), provides new opportunities for electronics and spintronics. However,
due to the presence of multiple orbital populations, tailoring the interfacial
properties such as the ground state and metal-insulator transitions remains
challenging. Here, we report an unforeseen tunability of the phase diagram of
LAO/STO by alloying LAO with a ferromagnetic LaMnO3 insulator without forming
lattice disorder and at the same time without changing the polarity of the
system. By increasing the Mn-doping level, x, of LaAl1-xMnxO3/STO, the
interface undergoes a Lifshitz transition at x = 0.225 across a critical
carrier density of nc= 2.8E13 cm-2, where a peak TSC =255 mK of superconducting
transition temperature is observed. Moreover, the LaAl1-xMnxO3 turns
ferromagnetic at x >=0.25. Remarkably, at x = 0.3, where the metallic interface
is populated by only dxy electrons and just before it becomes insulating, we
achieve reproducibly a same device with both signatures of superconductivity
and clear anomalous Hall effect. This provides a unique and effective way to
tailor oxide interfaces for designing on-demand electronic and spintronic
devices.Comment: 18 pages and 6 figure