Publications
Tests of nematic-mediated superconductivity applied to Ba1-xSrxNi2As2
In many unconventional superconductors, nematic quantum fluctuations are strongest where the critical temperature is highest, inviting the conjecture that nematicity plays an important role in the pairing mechanism. Recently, Ba1-xSrxNi2As2 has been identified as a tunable nematic system that provides an ideal testing ground for this proposition. We therefore propose several sharp empirical tests, supported by quantitative calculations in a simple model of Ba1-xSrxNi2As2.
Enhanced photoluminescence of MoS2–Au nanostructures: Nanotriangle and nanohole arrays
We investigated the photoluminescence (PL) characteristics of MoS2–Au hybrid nanostructures, fabricated by nanosphere lithography and wet-transfer techniques. Two kinds of Au nanostructures - such as nanotriangles (NTs) and nanoholes (NHs) - were fabricated for comparison. MoS2 monolayers on both NT and NH arrays exhibited enhanced PL intensity, compared with those on SiO2/Si substrates and flat Au thin films. Numerical simulations revealed clear distinction in the electric field intensity distributions in the NT and NH arrays at the PL excitation wavelength.
Heterogeneous matrix deposition in human tissue engineered cartilage changes the local shear modulus and resistance to local construct buckling
Human tissue engineered cartilage is a promising solution for focal cartilage defects, but these constructs do not have the same local mechanical properties as native tissue. Most clinically relevant engineered cartilage constructs seed human chondrocytes onto a collagen scaffold, which buckles at low loads and strains. This buckling creates local regions of high strain that could cause cell death and damage the engineered tissue.
Hypothesis for a mechanism of beam-induced motion in cryo-electron microscopy
Estimates of heat-transfer rates during plunge-cooling and the patterns of ice observed in cryo-EM samples indicate that the grid bars cool much more slowly than do the support foil and sample near the middle of the grid openings. The resulting transient temperature differences generate transient tensile stresses in the support foil. Most of this foil stress develops while the sample is liquid and cooling toward its glass transition T g, and so does not generate tensile sample stress.
Internal Fields in Multilayer WS2/MoS2 Heterostructures Epitaxially Grown on Sapphire Substrates
In conventional 3D heterostructures, a gradual potential gradient in constituent layers and an abrupt potential discontinuity at heterointerfaces can appear. Studies of the electrostatic potential in 2D heterostructures require careful characterizations and analyses because the 2D materials have distinct physical characteristics compared with their 3D counterparts. Herein, three kinds of samples are prepared using sulfurization of metal layers on single-crystalline sapphire substrates: WS2, MoS2, and WS2/MoS2.
Starting Dynamics of a Linear Mamyshev Oscillator
We investigate the starting dynamics of an environmentally-stable linear Mamyshev oscillator that is started by modulation of the pump power. A moving filter is implemented to generate 21-nJ and 65-fs pulses. © 2020 OSA.
Microscopic sensors using optical wireless integrated circuits
We present a platform for parallel production of standalone, untethered electronic sensors that are truly microscopic, i.e., smaller than the resolution of the naked eye. This platform heterogeneously integrates silicon electronics and inorganic microlight emitting diodes (LEDs) into a 100-μm-scale package that is powered by and communicates with light. The devices are fabricated, packaged, and released in parallel using photolithographic techniques, resulting in ∼10,000 individual sensors per square inch.
Embedding orthogonal memories in a colloidal gel through oscillatory shear
It has recently been shown that in a broad class of disordered systems oscillatory shear training can embed memories of specific shear protocols in relevant physical parameters such as the yield strain. These shear protocols can be used to change the physical properties of the system and memories of the protocol can later be "read" out. Here we investigate shear training memories in colloidal gels, which include an attractive interaction and network structure, and discover that such systems can support memories both along and orthogonal to the training flow direction.
MoS2 Monolayers on Au Nanodot Arrays: Surface Plasmon, Local Strain, and Interfacial Electronic Interaction
Metal and transition-metal dichalcogenide (TMD) hybrid systems have been attracting growing research attention because exciton-plasmon coupling is a desirable means of tuning the physical properties of TMD materials. Competing effects of metal nanostructures, such as the local electromagnetic field enhancement and luminescence quenching, affect the photoluminescence (PL) characteristics of metal/TMD nanostructures.
Imaging the energy gap modulations of the cuprate pair-density-wave state
The defining characteristic1,2 of Cooper pairs with finite centre-of-mass momentum is a spatially modulating superconducting energy gap Δ(r), where r is a position. Recently, this concept has been generalized to the pair-density-wave (PDW) state predicted to exist in copper oxides (cuprates)3,4. Although the signature of a cuprate PDW has been detected in Cooper-pair tunnelling5, the distinctive signature in single-electron tunnelling of a periodic Δ(r) modulation has not been observed.