12 research outputs found
Critical role of magnetic moments on lattice dynamics in YBaCuO
The role of lattice dynamics in unconventional high-temperature
superconductivity is still vigorously debated. Theoretical insights into this
problem have long been prevented by the absence of an accurate first-principles
description of the combined electronic, magnetic, and lattice degrees of
freedom. Utilizing the recently constructed rSCAN density functional that
stabilizes the antiferromagnetic (AFM) state of the pristine oxide
YBaCuO, we faithfully reproduce the experimental dispersion of key
phonon modes. We further find significant magnetoelastic coupling in numerous
high energy Cu-O bond stretching optical branches, where the AFM results
improve over the soft non-magnetic phonon bands
Observation of multiple van Hove singularities and correlated electronic states in a new topological ferromagnetic kagome metal NdTi3Bi4
Kagome materials have attracted enormous research interest recently owing to
its diverse topological phases and manifestation of electronic correlation due
to its inherent geometric frustration. Here, we report the electronic structure
of a new distorted kagome metal NdTi3Bi4 using a combination of angle resolved
photoemission spectroscopy (ARPES) measurements and density functional theory
(DFT) calculations. We discover the presence of two at bands which are found to
originate from the kagome structure formed by Ti atoms with major contribution
from Ti dxy and Ti dx2-y2 orbitals. We also observed multiple van Hove
singularities (VHSs) in its electronic structure, with one VHS lying near the
Fermi level EF. In addition, the presence of a surface Dirac cone at the G
point and a linear Dirac-like state at the K point with its Dirac node lying
very close to the EF indicates its topological nature. Our findings reveal
NdTi3Bi4 as a potential material to understand the interplay of topology,
magnetism, and electron correlation.Comment: 7 pages, 4 figure
Observation of multiple flat bands and topological Dirac states in a new titanium based slightly distorted kagome metal YbTi3Bi4
Kagome lattices have emerged as an ideal platform for exploring various
exotic quantum phenomena such as correlated topological phases, frustrated
lattice geometry, unconventional charge density wave orders, Chern quantum
phases, superconductivity, etc. In particular, the vanadium based nonmagnetic
kagome metals AV3Sb5 (A= K, Rb, and Cs) have seen a flurry of research interest
due to the discovery of multiple competing orders. Here, we report the
discovery of a new Ti based kagome metal YbTi3Bi4 and employ angle-resolved
photoemission spectroscopy (ARPES), magnetotransport in combination with
density functional theory calculations to investigate its electronic structure.
We reveal spectroscopic evidence of multiple flat bands arising from the kagome
lattice of Ti with predominant Ti 3d character. Through our calculations of the
Z2 indices, we have identified that the system exhibits topological
nontriviality with surface Dirac cones at the Gamma point and a quasi
two-dimensional Dirac state at the K point which is further confirmed by our
ARPES measured band dispersion. These results establish YbTi3Bi4 as a novel
platform for exploring the intersection of nontrivial topology, and electron
correlation effects in this newly discovered Ti based kagome lattice.Comment: 8 pages, 5 figure
Second Dome of Superconductivity in YBaCuO at High Pressure
Evidence is growing that a second dome of high-
superconductivity can be accessed in the cuprates by increasing the doping
beyond the first dome. Here we use \emph{ab initio} methods without invoking
any free parameters such as the Hubbard , to reveal that pressure could turn
YBaCuO into an ideal candidate for second-dome-superconductivity,
displaying the predicted signature of strongly hybridized and
orbitals. Notably, pressure is found to induce a phase transition
replacing the antiferromagnetic phases with an orbitally-degenerate -
phase. We find an interesting doping-dependence of the oxygen-hole fraction in
the CuO planes, which suggests the presence of a second dome
Data from: Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors
At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature
Robomussel data
Robomussel data: intertidal biomimic body temperature of mussels deployed at 6 different countries. 1913 .txt files in total. Files are categorized by location (country, region, site). In addition, metadata file show specific information for loggers at each site