30 research outputs found
Engineering 2D material exciton lineshape with graphene/h-BN encapsulation
Control over the optical properties of atomically thin two-dimensional (2D)
layers, including those of transition metal dichalcogenides (TMDs), is needed
for future optoelectronic applications. Remarkable advances have been achieved
through alloying, chemical and electrical doping, and applied strain. However,
the integration of TMDs with other 2D materials in van der Waals
heterostructures (vdWHs) to tailor novel functionalities remains largely
unexplored. Here, the near-field coupling between TMDs and graphene/graphite is
used to engineer the exciton lineshape and charge state. Fano-like asymmetric
spectral features are produced in WS, MoSe and WSe vdWHs
combined with graphene, graphite, or jointly with hexagonal boron nitride
(h-BN) as supporting or encapsulating layers. Furthermore, trion emission is
suppressed in h-BN encapsulated WSe/graphene with a neutral exciton
redshift (44 meV) and binding energy reduction (30 meV). The response of these
systems to electron-beam and light probes is well-described in terms of 2D
optical conductivities of the involved materials. Beyond fundamental insights
into the interaction of TMD excitons with structured environments, this study
opens an unexplored avenue toward shaping the spectral profile of narrow
optical modes for application in nanophotonic devices
Common marmoset (Callithrix jacchus) personality, subjective well-being, hair cortisol level and AVPR1a, OPRM1, and DAT genotypes
We studied personality, subjective well-being, and hair cortisol level, in common marmosets Callithrix jacchus, a small, cooperatively breeding New World monkey, by examining their associations with one another and genotypes. Subjects were 68 males and 9 females that lived in the RIKEN Center for Life Science Technologies. Personality and subjective well-being were assessed by keeper ratings on two questionnaires, hair samples were obtained to assay cortisol level and buccal swabs were used to assess AVPR1a, OPRM1 and DAT genotypes. Three personality domains—Dominance, Sociability, and Neuroticism—were identified. Consistent with findings in other species, Sociability and Neuroticism were related to higher and lower subjective well-being, respectively. Sociability was also associated with higher hair cortisol levels. The personality domains and hair cortisol levels were heritable and associated with genotypes: the short form of AVPR1a was associated with lower Neuroticism and the AA genotype of the A111T SNP of OPRM1 was related to lower Dominance, lower Neuroticism, and higher hair cortisol level. Some genetic associations were not in directions that one would expect given findings in other species. These findings provide insights into the proximate and ultimate bases of personality in common marmosets, other primates and humans