Unconventional correlated insulator in CrOCl-interfaced Bernal bilayer graphene.

The realization of graphene gapped states with large on/off ratios over wide doping ranges remains challenging. Here, we investigate heterostructures based on Bernal-stacked bilayer graphene (BLG) atop few-layered CrOCl, exhibiting an over-1-GΩ-resistance insulating state in a widely accessible gate voltage range. The insulating state could be switched into a metallic state with an on/off ratio up to 107 by applying an in-plane electric field, heating, or gating. We tentatively associate the observed behavior to the formation of a surface state in CrOCl under vertical electric fields, promoting electron-electron (e-e) interactions in BLG via long-range Coulomb coupling. Consequently, at the charge neutrality point, a crossover from single particle insulating behavior to an unconventional correlated insulator is enabled, below an onset temperature. We demonstrate the application of the insulating state for the realization of a logic inverter operating at low temperatures. Our findings pave the way for future engineering of quantum electronic states based on interfacial charge coupling.

Mobile Device Ownership, Current Use, and Interest in Mobile Health Interventions Among Low-Income Older Chinese Immigrants With Type 2 Diabetes: Cross-sectional Survey Study.

BACKGROUND: Chinese immigrants suffer a disproportionately high type 2 diabetes (T2D) burden and tend to have poorly controlled disease. Mobile health (mHealth) interventions have been shown to increase access to care and improve chronic disease management in minority populations. However, such interventions have not been developed for or tested in Chinese immigrants with T2D. OBJECTIVE: This study aims to examine mobile device ownership, current use, and interest in mHealth interventions among Chinese immigrants with T2D. METHODS: In a cross-sectional survey, Chinese immigrants with T2D were recruited from Chinese community centers in New York City. Sociodemographic characteristics, mobile device ownership, current use of social media software applications, current use of technology for health-related purposes, and interest in using mHealth for T2D management were assessed. Surveys were administered face-to-face by bilingual study staff in the participant's preferred language. Descriptive statistics were used to characterize the study sample and summarize technology use. RESULTS: The sample (N=91) was predominantly female (n=57, 63%), married (n=68, 75%), and had a high school education or less (n=58, 64%); most participants had an annual household income of less than US $25,000 (n=63, 69%) and had limited English proficiency (n=78, 86%). The sample had a mean age of 70 (SD 11) years. Almost all (90/91, 99%) participants had a mobile device (eg, basic cell phones, smart devices), and the majority (n=83, 91%) reported owning a smart device (eg, smartphone or tablet). WeChat was the most commonly used social media platform (65/91, 71%). When asked about their top source for diabetes-related information, 63 of the 91 participants (69%) reported health care providers, followed by 13 who reported the internet (14%), and 10 who reported family, friends, and coworkers (11%). Less than one-quarter (21/91, 23%) of the sample reported using the internet to search for diabetes-related information in the past 12 months. About one-third of the sample (34/91, 37%) reported that they had watched a health-related video on their cell phone or computer in the past 12 months. The majority (69/91, 76%) of participants reported interest in receiving an mHealth intervention in the future to help with T2D management. CONCLUSIONS: Despite high mobile device ownership, the current use of technology for health-related issues remained low in older Chinese immigrants with T2D. Given the strong interest in future mHealth interventions and high levels of social media use (eg, WeChat), future studies should consider how to leverage these existing low-cost platforms and deliver tailored mHealth interventions to this fast-growing minority group.

Electrically switchable van der Waals magnon valves.

Van der Waals magnets have emerged as a fertile ground for the exploration of highly tunable spin physics and spin-related technology. Two-dimensional (2D) magnons in van der Waals magnets are collective excitation of spins under strong confinement. Although considerable progress has been made in understanding 2D magnons, a crucial magnon device called the van der Waals magnon valve, in which the magnon signal can be completely and repeatedly turned on and off electrically, has yet to be realized. Here we demonstrate such magnon valves based on van der Waals antiferromagnetic insulator MnPS3. By applying DC electric current through the gate electrode, we show that the second harmonic thermal magnon (SHM) signal can be tuned from positive to negative. The guaranteed zero crossing during this tuning demonstrates a complete blocking of SHM transmission, arising from the nonlinear gate dependence of the non-equilibrium magnon density in the 2D spin channel. Using the switchable magnon valves we demonstrate a magnon-based inverter. These results illustrate the potential of van der Waals anti-ferromagnets for studying highly tunable spin-wave physics and for application in magnon-base circuitry in future information technology.

Anisotropic Raman spectrum and transport properties of AuTe2Br flakes.

Topological semimetal (TSM) AuTe2Br thin flakes have been studied by Raman spectroscopy and magneto-transport measurement. The angle-resolved polarized Raman spectrum of AuTe2Br (bulk and thin flake) shows strong anisotropy. Together with high resolution transmission electron microscopy (TEM), we establish a non-destructive method to determine the crystallographic orientation of AuTe2Br flakes. At high temperature (T > 50 K), the magneto-resistance (MR) of AuTe2Br thin flakes shows typical parabolic-like behavior, which can be well fitted by the two-fluid model. However, at low temperature (T ⩽ 30 K), the MR of thin flakes (<17 nm) clearly deviates from the two-fluid model as well as from the Kohler's rule, suggesting a new type of scattering emerging below 30 K. Several possible scattering mechanisms are discussed and the respective corrections to MR are compared with our experimental data. In addition, the conductivity of these metallic crystals is also found to be highly anisotropic, with the hole mobility along the a axis about five times higher than that along the c axis.

Gate tunable giant anisotropic resistance in ultra-thin GaTe.

Anisotropy in crystals arises from different lattice periodicity along different crystallographic directions, and is usually more pronounced in two dimensional (2D) materials. Indeed, in the emerging 2D materials, electrical anisotropy has been one of the recent research focuses. However, key understandings of the in-plane anisotropic resistance in low-symmetry 2D materials, as well as demonstrations of model devices taking advantage of it, have proven difficult. Here, we show that, in few-layered semiconducting GaTe, electrical conductivity anisotropy between x and y directions of the 2D crystal can be gate tuned from several fold to over 103. This effect is further demonstrated to yield an anisotropic non-volatile memory behavior in ultra-thin GaTe, when equipped with an architecture of van der Waals floating gate. Our findings of gate-tunable giant anisotropic resistance effect pave the way for potential applications in nanoelectronics such as multifunctional directional memories in the 2D limit.

Investigation of valley-resolved transmission through gate defined graphene carrier guiders.

Massless charge carriers in gate potentials modulate graphene quantum well transport in the same way that a electromagnetic wave propagates in optical fibers. A recent experiment by Kim et al (2016 Nat. Phys. 12 1022) reports valley symmetry preserved transport in a graphene carrier guider. Based on a tight-binding model, the valley-resolved transport coefficients are calculated with the method of scattering matrix theory. For a straight potential well, valley-resolved conductance is quantized with a value of 2n + 1 and multiplied by 2e 2/h with integer n. In the absence of disorder, intervalley scattering, only occurring at both ends of the potential well, is weak. The propagating modes inside the potential well are analyzed with the help of band structure and wave function distribution. The conductance is better preserved for a longer carrier guider. The quantized conductance is barely affected by the boundaries of different types or slightly changing the orientation of the carrier guider. For a curved model, the state with momentum closes to the neutral point is more fragile to boundary scattering and the quantized conductance is ruined as well.

Design and demonstration of a new kind of aperture for getting expected diffraction patterns.

In the regime of Fresnel diffraction, a novel algorithm is proposed for aperture design for getting expected diffraction patterns. Experiments have verified the feasibility of this method. It may be used in beam transition, optics communication, information encryption, and other related fields.

Decreased circulating levels of tumor necrosis factor-alpha in postmenopausal women during consumption of soy-containing isoflavones.

CONTEXT: TNF-alpha is a key mediator of inflammatory responses and may play a pivotal role in the development of cancer and in bone resorption. OBJECTIVE: This study determined the effect of soy rich in isoflavones on levels of TNF-alpha. DESIGN: Twelve postmenopausal women ingested a 36-oz portion of soymilk containing isoflavones daily for 16 wk and provided fasting blood samples multiple times before, during, and after soy consumption for the analyses of cytokines and monocyte content. RESULTS: Compared with prediet levels (36.3 +/- 14.0 pg/ml), serum levels of TNF-alpha decreased by 25.1% (27.2 +/- 10.3 pg/ml; P < 0.01) as early as 2 wk after soy consumption and by 66.7% (11.6 +/- 5.3 pg/ml; P < 0.01) 10 wk after soy consumption and recovered to the prediet levels 4 wk after the termination of soy consumption (38.6 +/- 19.6 pg/ml; P = 0.66). A similar decrease of up to 56.6 and 14.4% was found for serum IL-1alpha and the mean percentage of blood monocytes during soy consumption, respectively, but not for IL-6. In cultures of monocytes or whole blood from postmenopausal women, soy isoflavones (genistein and daidzein, 10-1000 nm), tamoxifen (10-1000 nm), or 17beta-estradiol (0.1-10 nm) inhibited lipopolysaccharide (1 microg/ml)-induced TNF-alpha production by up to 55.8%. CONCLUSIONS: Isoflavones may be the active components in soy responsible for the decrease of TNF-alpha found in postmenopausal women during a soy diet. This antiinflammatory effect of the isoflavones may be important in immune modulation and the prevention of bone loss and cancer.