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Publications

Tunable nanophotonic array traps with enhanced force and stability

Cornell Affiliated Author(s)
Author
F. Ye
M. Soltani
J.T. Inman
M.D. Wang
Abstract

A nanophotonic trapping platform based on on-chip tunable optical interference allows parallel processing of biomolecules and holds promise to make single molecule manipulation and precision measurements more easily and broadly available. The nanophotonic standing wave array trap (nSWAT) device [Nat. Nanotechnol. 9, 448 (2014); Nano Lett. 16, 6661 (2016)] represents such a platform and can trap a large array of beads by the evanescent field of the standing wave of a nanophotonic waveguide and reposition them using an integrated microheater.

Journal
Optics Express
Date Published
Research Area
Group (Lab)
Michelle Wang Group

High Dynamic Range X-Ray Detector Pixel Architectures Utilizing Charge Removal

Cornell Affiliated Author(s)
Author
J.T. Weiss
K.S. Shanks
H.T. Philipp
J. Becker
Darol Chamberlain
P. Purohit
M.W. Tate
Sol Gruner
Abstract

Several charge integrating CMOS pixel front ends utilizing charge removal techniques have been fabricated to extend dynamic range for X-ray diffraction applications at synchrotron sources and X-ray free electron lasers (XFELs). The pixels described herein build on the mixed mode pixel array detector (MM-PAD) framework, developed previously by our group to perform high dynamic range imaging.

Journal
IEEE Transactions on Nuclear Science
Date Published
Funding Source
DMR-1332208
DE-FG02-10ER46693
DE-SC0016035
1332208
Group (Lab)
Sol M. Gruner Group

Nematic fluctuations balancing the zoo of phases in half-filled quantum Hall systems

Cornell Affiliated Author(s)
Author
A. Mesaros
M.J. Lawler
Eun-Ah Kim
Abstract

Half-filled Landau levels form a zoo of strongly correlated phases. These include non-Fermi-liquids (NFLs), fractional quantum Hall (FQH) states, nematic phases, and FQH nematic phases. This diversity begs the following question: what keeps the balance between the seemingly unrelated phases? The answer is elusive because the Halperin-Lee-Read description that offers a natural departure point is inherently strongly coupled. However, the observed nematic phases suggest that nematic fluctuations play an important role.

Journal
Physical Review B
Date Published
Group (Lab)
Michael Lawler Group

Thermodynamic constraints on the amplitude of quantum oscillations

Cornell Affiliated Author(s)
Author
Arkady Shekhter
K. Modic
R. McDonald
B. Ramshaw
Abstract

Magneto-quantum oscillation experiments in high-temperature superconductors show a strong thermally induced suppression of the oscillation amplitude approaching the critical dopings [B. J. Ramshaw, Science 348, 317 (2014)SCIEAS0036-807510.1126/science.aaa4990; H. Shishido, Phys. Rev. Lett. 104, 057008 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.057008; P. Walmsley, Phys. Rev. Lett. 110, 257002 (2013)PRLTAO0031-900710.1103/PhysRevLett.110.257002] - in support of a quantum-critical origin of their phase diagrams.

Journal
Physical Review B
Date Published
Funding Source
PHY-1066293
DMR-1157490
1066293
1157490
Group (Lab)
Brad Ramshaw Group

Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry

Cornell Affiliated Author(s)
Author
R. Sundararaman
W.A. Goddard III
Tomas Arias
Abstract

First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition.

Journal
Journal of Chemical Physics
Date Published
Funding Source
DE-SC0004993
DE-AC02-05CH11231
DE-SC0001086
Group (Lab)
Tomas Arias Group

Nanosecond magnetization dynamics during spin Hall switching of in-plane magnetic tunnel junctions

Cornell Affiliated Author(s)
Author
G. Rowlands
Sriharsha Aradhya
S. Shi
E. Yandel
J. Oh
D. Ralph
Robert Buhrman
Abstract

We present a study of the magnetic dynamics associated with nanosecond scale magnetic switching driven by the spin Hall effect in 3-terminal nanoscale magnetic tunnel junctions (MTJs) with in-plane magnetization.

Journal
AIP Publishing
Date Published
Funding Source
ECCS-0335765
0335765
W911NF-14-C0089
DMR-1120296

Surface atomic structure of epitaxial LaNiO3 thin films studied by in situ LEED- I(V)

Cornell Affiliated Author(s)
Author
J.P. Ruf
P.D.C. King
V.B. Nascimento
D.G. Schlom
K.M. Shen
Abstract

We report in situ low-energy electron diffraction intensity versus voltage [LEED-I(V)] studies of the surface atomic structure of epitaxially grown (001)pc-oriented (pc=pseudocubic) thin films of the correlated 3d transition-metal oxide LaNiO3. Our analysis indicates the presence of large out-of-plane bucklings of the topmost LaO layers but only minor bucklings of the topmost NiO2 layers, in close agreement with earlier surface x-ray diffraction data.

Journal
Physical Review B
Date Published
Funding Source
APQ-01961-14
DMR-1120296
DGE-0903653
N00014-12-1-0791
Group (Lab)
Kyle Shen Group

Influence of Surface Adsorption on the Oxygen Evolution Reaction on IrO2(110)

Cornell Affiliated Author(s)
Author
D.-Y. Kuo
J.K. Kawasaki
J.N. Nelson
J. Kloppenburg
G. Hautier
K.M. Shen
D.G. Schlom
J. Suntivich
Abstract

A catalyst functions by stabilizing reaction intermediates, usually through surface adsorption. In the oxygen evolution reaction (OER), surface oxygen adsorption plays an indispensable role in the electrocatalysis. The relationship between the adsorption energetics and OER kinetics, however, has not yet been experimentally measured. Herein we report an experimental relationship between the adsorption of surface oxygen and the kinetics of the OER on IrO2(110) epitaxially grown on a TiO2(110) single crystal.

Journal
Journal of the American Chemical Society
Date Published
Funding Source
DMR-1120296
DGE-1650441
ECCS-0335765
2.5020.11
Group (Lab)
Kyle Shen Group

Characterization and control of ZnGeN2 cation lattice ordering

Cornell Affiliated Author(s)
Author
E.W. Blanton
K. He
J. Shan
K. Kash
Abstract

ZnGeN2 and other heterovalent ternary semiconductors have important potential applications in optoelectronics, but ordering of the cation sublattice, which can affect the band gap, lattice parameters, and phonons, is not yet well understood. Here the effects of growth and processing conditions on the ordering of the ZnGeN2 cation sublattice were investigated using x-ray diffraction and Raman spectroscopy. Polycrystalline ZnGeN2 was grown by exposing solid Ge to Zn and NH3 vapors at temperatures between 758 °C and 914 °C.

Journal
Journal of Crystal Growth
Date Published
Funding Source
1006132
1106225
1409346
Group (Lab)
Jie Shan Group

Control of spin–orbit torques through crystal symmetry in WTe2/ferromagnet bilayers

Cornell Affiliated Author(s)
Author
D. Macneill
G. Stiehl
Marcos Guimarães
Robert Buhrman
J. Park
D. Ralph
Abstract

Recent discoveries regarding current-induced spin-orbit torques produced by heavy-metal/ferromagnet and topological-insulator/ferromagnet bilayers provide the potential for dramatically improved efficiency in the manipulation of magnetic devices. However, in experiments performed to date, spin-orbit torques have an important limitation - the component of torque that can compensate magnetic damping is required by symmetry to lie within the device plane.

Journal
Springer Science and Business Media LLC
Date Published
Funding Source
DGE-1144153
DMR-1120296
DMR-1539918
ECCS-1542081
NWO 680-50-1311
1406333
1539918
DMR-1406333
W911NF-15-1-0447
680-50-1311