6,027 research outputs found
Controllable quantum spin precession by Aharonov-Casher phase in conducting ring
We investigate quantum spin transport in a structure of conducting ring,
embedded in textured electric field, with two leads, and obtain an exact
solution for the problem. The spin precession induced by the Aharonov-Casher
phase is studied. It is shown that the spin-polarized current and its
polarizability can be controlled by the electric field. As a result the
polarizability is a function of the geometric phase which originates from the
spin-orbital interaction in the ring.
72.25.-b, 03.65.VfComment: 10 pages, 4 figure
Electrically Tunable Energy Bandgap in Dual-Gated Ultra-Thin Black Phosphorus Field Effect Transistors
The energy bandgap is an intrinsic character of semiconductors, which largely
determines their properties. The ability to continuously and reversibly tune
the bandgap of a single device during real time operation is of great
importance not only to device physics but also to technological applications.
Here we demonstrate a widely tunable bandgap of few-layer black phosphorus (BP)
by the application of vertical electric field in dual-gated BP field-effect
transistors. A total bandgap reduction of 124 meV is observed when the
electrical displacement field is increased from 0.10V/nm to 0.83V/nm. Our
results suggest appealing potential for few-layer BP as a tunable bandgap
material in infrared optoelectronics, thermoelectric power generation and
thermal imaging.Comment: 5 pages, 4 figure
Genome-wide association analysis identifies resistance loci for bacterial blight in a diverse collection of indica rice germplasm
Bacterial blight, which is caused by Xanthomonas oryzae pv. oryzae (Xoo), is one of the most devastating rice diseases worldwide. The development and use of disease-resistant cultivars have been the most effective strategy to control bacterial blight. Identifying the genes mediating bacterial blight resistance is a prerequisite for breeding cultivars with broad-spectrum and durable resistance. We herein describe a genome-wide association study involving 172 diverse Oryza sativa ssp. indica accessions to identify loci influencing the resistance to representative strains of six Xoo races. Twelve resistance loci containing 121 significantly associated signals were identified using 317,894 single nucleotide polymorphisms, which explained 13.3–59.9% of the variability in lesion length caused by Xoo races P1, P6, and P9a. Two hotspot regions (L11 and L12) were located within or nearby two cloned R genes (xa25 and Xa26) and one fine-mapped R gene (Xa4). Our results confirmed the relatively high resolution of genome-wide association studies. Moreover, we detected novel significant associations on chromosomes 2, 3, and 6–10. Haplotype analyses of xa25, the Xa26 paralog (MRKc; LOC_Os11g47290), and a Xa4 candidate gene (LOC_11g46870) revealed differences in bacterial blight resistance among indica subgroups. These differences were responsible for the observed variations in lesion lengths resulting from infections by Xoo races P1 and P9a. Our findings may be relevant for future studies involving bacterial blight resistance gene cloning, and provide insights into the genetic basis for bacterial blight resistance in indica rice, which may be useful for knowledge-based crop improvement. (Résumé d'auteur
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