Search

The optical momentum alignment effect is demonstrated in WSe2 phototransistors. When the photon energy is above the A exciton energy, the maximum photocurrent response occurs for the light polarization direction parallel to the metal electrode edge, suggesting that electrons in the valence band of WSe2 prefer to absorb photons with the polarization direction perpendicular to their momentum direction. Further studies indicate that the anisotropic distribution of photo‐excited carriers is likely due to the pseudospin‐induced optical transition selection rules. If the photon energy is below the A exciton energy, the photocurrent signals are maximized when the incident light is polarized in the direction perpendicular to the electrode edge, which is mainly attributed to the polarized absorption of the plasmonic gold electrodes. Moreover, the photocurrent peak can be controlled by an electric field via the quantum confined Stark effect. This resonance peak can also be shifted by adjusting environmental temperatures due to the temperature‐dependent nature of the WSe2 band gap. These experimental studies shed light on the knowledge of photocurrent generation mechanisms, opening the door for engineering future anisotropic optoelectronics. [ABSTRACT FROM AUTHOR]

The conversion of skeletal muscle fiber from fast twitch to slow‐twitch is important for sustained and tonic contractile events, maintenance of energy homeostasis, and the alleviation of fatigue. Skeletal muscle remodeling is effectively induced by endurance or aerobic exercise, which also generates several tricarboxylic acid (TCA) cycle intermediates, including succinate. However, whether succinate regulates muscle fiber‐type transitions remains unclear. Here, we found that dietary succinate supplementation increased endurance exercise ability, myosin heavy chain I expression, aerobic enzyme activity, oxygen consumption, and mitochondrial biogenesis in mouse skeletal muscle. By contrast, succinate decreased lactate dehydrogenase activity, lactate production, and myosin heavy chain IIb expression. Further, by using pharmacological or genetic loss‐of‐function models generated by phospholipase Cβ antagonists, SUNCR1 global knockout, or SUNCR1 gastrocnemius‐specific knockdown, we found that the effects of succinate on skeletal muscle fiber‐type remodeling are mediated by SUNCR1 and its downstream calcium/NFAT signaling pathway. In summary, our results demonstrate succinate induces transition of skeletal muscle fiber via SUNCR1 signaling pathway. These findings suggest the potential beneficial use of succinate‐based compounds in both athletic and sedentary populations. Synopsis: Aerobic exercise leads to skeletal muscle remodelling. This study reveals that dietary succinate is sufficient to elicit muscle remodelling and increased endurance in sedentary mice. Dietary succinate increases endurance exercise ability in mice.Dietary succinate induces skeletal muscle fiber transition from fast‐twitch to slow‐twitch.SUNCR1 signaling pathway is required for the succinate induced skeletal muscle remodeling. [ABSTRACT FROM AUTHOR]

Gate‐/wavelength‐dependent scanning photocurrent measurements of black phosphorous (BP)–MoS2 heterojunctions have shown that the Schottky barrier at the MoS2–metal interface plays an important role in the photoresponse dynamics of the heterojunction. When the Fermi level is close to the conduction band of MoS2, photoexcited carriers can tunnel through the narrow depletion region at the MoS2–metal interface, leading to a short response time of 13 µs regardless of the incident laser wavelength. This response speed is comparable or better than that of other few‐layer BP–MoS2 heterojunctions. Conversely, when the MoS2 channel is in the off‐state, the resulting sizeable Schottky barrier and depletion width make it difficult for photoexcited carriers to overcome the barrier. This significantly delays the carrier transit time and thus the photoresponse speed, leading to a wavelength‐dependent response time since the photoexcited carriers induced by short wavelength photons have a higher probability to overcome the Schottky barrier at the MoS2–metal interface than long wavelength photons. These studies not only shed light on the fundamental understanding of photoresponse dynamics in BP–MoS2 heterojunctions, but also open new avenues for engineering the interfaces between 2D materials and metal contacts to reduce the response time of 2D optoelectronics. Wavelength‐ and gate‐dependent photoresponse speed is demonstrated in black phosphorus (BP)–MoS2 heterojunctions. Through modulating the Schottky barrier at the MoS2–metal interface with an applied gate voltage photoexcited carriers are either able to easily tunnel through or unable to overcome this barrier, shedding light on the significance of this barrier in the photoresponse dynamics of 2D materials. [ABSTRACT FROM AUTHOR]