7 research outputs found
Molecular Beam Epitaxy growth of MoTe on Hexagonal Boron Nitride
Hexagonal boron nitride has already been proven to serve as a decent
substrate for high quality epitaxial growth of several 2D materials, such as
graphene, MoSe, MoS or
WSe. Here, we present for the first time the molecular
beam epitaxy growth of MoTe on atomically smooth
hexagonal boron nitride (hBN) substrate. Occurrence of
MoTe in various crystalline phases such as distorted
octahedral 1T' phase with semimetal properties or hexagonal 2H phase with
semiconducting properties opens a possibility of realisation of crystal-phase
homostructures with tunable properties. Atomic force microscopy studies of
MoTe grown in a single monolayer regime enable us to
determine surface morphology as a function of the growth conditions. The
diffusion constant of MoTe grown on hBN can be altered 5
times by annealing after the growth, reaching about 5 10
cm/s. Raman spectroscopy results suggest a coexistence of both 2H and 1T'
MoTe phases in the studied samples.Comment: 6 pages, 3 figure
Natural exceptional points in the excitation spectrum of a light-matter system
We observe natural exceptional points in the excitation spectrum of an
exciton-polariton system by optically tuning the light-matter interactions. The
observed exceptional points do not require any spatial or polarization degrees
of freedom and result solely from the transition from weak to strong
light-matter coupling. We demonstrate that they do not coincide with the
threshold for photon lasing, confirming previous theoretical predictions [Phys.
Rev. Lett. 122, 185301 (2019), Optica 7, 1015 (2020) ]. Using a technique where
a strong coherent laser pump induces up-converted excitations, we encircle the
exceptional point in the parameter space of coupling strength and particle
momentum. Our method of local optical control of light-matter coupling paves
the way to investigation of fundamental phenomena including dissipative phase
transitions and non-Hermitian topological states
Impact of marathon performance on muscles stiffness in runners over 50 years old
IntroductionThe research examines the relationship between marathon performance and muscle stiffness changes from pre to marathon in recreational runners aged 50+ years.MethodsThirty-one male long-distance runners aged 50–73 years participated in the experiment. The muscle stiffness of quadriceps and calves was measured in two independent sessions: the day before the marathon and 30 min after the completed marathon run using a Myoton device.Results and DiscussionThe 42.195-km run was completed in 4.30,05 h ± 35.12 min, which indicates an intensity of 79.3% ± 7.1% of HRmax. The long-term, low-intensity running exercise (marathon) in older recreational runners and the low level of HRmax and VO2max showed no statistically significant changes in muscle stiffness (quadriceps and calves). There was reduced muscle stiffness (p = 0.016), but only in the triceps of the calf in the dominant (left) leg. Moreover, to optimally evaluate the marathon and adequately prepare for the performance training program, we need to consider the direct and indirect analyses of the running economy, running technique, and HRmax and VO2max variables. These variables significantly affect marathon exercise