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Publications

Optimal wing hinge position for fast ascent in a model fly

Cornell Affiliated Author(s)
Author
R.M. Noest
Jane Wang
Abstract

It was thought that the wing hinge position can be tuned to stabilize an uncontrolled fly. However here, our Floquet stability analysis shows that the hinge position has a weak dependence on the flight stability. As long as the hinge position is within the fly's body length, both hovering and ascending flight are unstable. Instead, there is an optimal hinge position, , at which the ascending speed is maximized. is approximately half way between the centre of mass and the top of the body.

Journal
Journal of Fluid Mechanics
Date Published
Research Area
Group (Lab)
Z. Jane Wang Group

Rewiring stabilizer codes

Cornell Affiliated Author(s)
Author
K.R. Colladay
E.J. Mueller
Abstract

We present an algorithm for manipulating quantum information via a sequence of projective measurements. We frame this manipulation in the language of stabilizer codes: A quantum computation approach in which errors are prevented and corrected in part by repeatedly measuring redundant degrees of freedom. We show how to construct a set of projective measurements which will map between two arbitrary stabilizer codes. We show that this process preserves all quantum information.

Journal
New Journal of Physics
Date Published
Funding Source
1508300

Structural, magnetic, and transport properties of Fe1- xRhx/MgO(001) films grown by molecular-beam epitaxy

Cornell Affiliated Author(s)
Author
A.B. Mei
Y. Tang
J.L. Grab
J. Schubert
D.C. Ralph
D.G. Schlom
Abstract

Fe1- xRhx layers are grown with varying rhodium fraction x on (001)-oriented MgO substrates by molecular-beam epitaxy. Film structural, morphological, magnetic, and transport properties are investigated. At room temperature, layers are ferromagnetic (FM) for x < 0.48 and antiferromagnetic (AF) for x > 0.48. Separating the two magnetically ordered phases at x = 0.48 is an abrupt change in the Fe1- xRhx lattice parameter of Δa = 0.0028 nm (Δa/a =-0.9%). For AF layers, the FM state is recovered by heating across a first-order phase transition.

Journal
Applied Physics Letters
Date Published
Funding Source
1740286
ECCS-1740136
2758.001
2758.003

Young's modulus and thermal expansion of tensioned graphene membranes

Cornell Affiliated Author(s)
Author
I.R. Storch
R. De Alba
V.P. Adiga
T.S. Abhilash
R.A. Barton
H.G. Craighead
J.M. Parpia
P.L. McEuen
Abstract

Tensioned graphene membranes are of interest both for fundamental physics and for applications ranging from water filtration to nanomechanical resonators. It is generally assumed that these membranes have a stretching modulus of about 340 N/m and a negative, temperature-independent thermal expansion coefficient due to transverse phonon modes. In this paper, we study the two-dimensional Young's modulus and thermal expansion of graphene as functions of temperature by using laser interferometry to detect the static displacement of the membrane in a cryostat.

Journal
Physical Review B
Date Published
Funding Source
DMR-1719875
ECCS-1542081
DGE-0903653
FA9550-16-1-0031
Group (Lab)
Jeevak Parpia Group
Paul McEuen Group

Scale-invariant magnetoresistance in a cuprate superconductor

Cornell Affiliated Author(s)
Author
P. Giraldo-Gallo
J. Galvis
Z. Stegen
K. Modic
Fedor Balakirev
Jon Betts
X. Lian
C. Moir
S. Riggs
J. Wu
A. Bollinger
X. He
I. Božović
B. Ramshaw
R. McDonald
G.S. Boebinger
A. Shekhter
Abstract

The anomalous metallic state in the high-temperature superconducting cuprates is masked by superconductivity near a quantum critical point. Applying high magnetic fields to suppress superconductivity has enabled detailed studies of the normal state, yet the direct effect of strong magnetic fields on the metallic state is poorly understood. We report the high-field magnetoresistance of thin-film La2–xSrxCuO4 cuprate in the vicinity of the critical doping, 0.161 ≤ p ≤ 0.190.

Journal
Science
Date Published
Funding Source
1066293
1157490
DMR-1157490
Group (Lab)
Brad Ramshaw Group

Light–valley interactions in 2D semiconductors

Cornell Affiliated Author(s)
Author
K.F. Mak
D. Xiao
J. Shan
Abstract

The emergence of two-dimensional Dirac materials, particularly transition metal dichalcogenides (TMDs), has reinvigorated interest in valleytronics, which utilizes the electronic valley degree of freedom for information storage and processing. Here, we review the basic valley-dependent properties and their experimental demonstrations in single-layer semiconductor TMDs with an emphasis on the effects of band topology and light–valley interactions.

Journal
Nature Photonics
Date Published
Funding Source
1433496
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Topological kinematics of origami metamaterials

Cornell Affiliated Author(s)
Author
B. Liu
J.L. Silverberg
A.A. Evans
C.D. Santangelo
R.J. Lang
T.C. Hull
Itai Cohen
Abstract

A variety of electronic phases in solid-state systems can be understood by abstracting away microscopic details and refocusing on how Fermi surface topology interacts with band structure to define available electron states 1 . In fact, topological concepts are broadly applicable to non-electronic materials and can be used to understand a variety of seemingly unrelated phenomena 2–6 . Here, we apply topological principles to origami-inspired mechanical metamaterials 7–12 , and demonstrate how to guide bulk kinematics by tailoring the crease configuration-space topology.

Journal
Nature Physics
Date Published
Funding Source
1706511
Group (Lab)
Itai Cohen Group

Revealing the hidden heavy Fermi liquid in CaRuO3

Cornell Affiliated Author(s)
Author
Y. Liu
H.P. Nair
J.P. Ruf
D.G. Schlom
K.M. Shen
Abstract

The perovskite ruthenate CaRuO3 has attracted considerable interest due to reports of possible non-Fermi-liquid behavior and its proximity to a magnetic quantum critical point, yet its ground state and electronic structure remain enigmatic. Here, we report measurements of the Fermi surface and quasiparticle dispersion in CaRuO3 through a combination of oxide molecular beam epitaxy and in situ angle-resolved photoemission spectroscopy.

Journal
Physical Review B
Date Published
Funding Source
2016YFA0300203
DMR-1719875
0335765
0847385
1308089
1709255
DMR-1308089
DMR-1709255
2002S
11674280
Group (Lab)
Kyle Shen Group

Translationally Invariant Non-Fermi-Liquid Metals with Critical Fermi Surfaces: Solvable Models

Cornell Affiliated Author(s)
Author
Debanjan Chowdhury
Yochai Werman
Erez Berg
T. Senthil
Abstract

We construct examples of translationally invariant solvable models of strongly correlated metals, composed of lattices of Sachdev-Ye-Kitaev dots with identical local interactions. These models display crossovers as a function of temperature into regimes with local quantum criticality and marginal-Fermi-liquid behavior. In the marginal-Fermi-liquid regime, the dc resistivity increases linearly with temperature over a broad range of temperatures. By generalizing the form of interactions, we also construct examples of non-Fermi liquids with critical Fermi surfaces.

Journal
Physical Review X
Date Published
Funding Source
PHY-1125915
PHY-1607611
DE-SC0008739
GBMF-4303
Group (Lab)
Debanjan Chowdhury Group

Dynamical susceptibility of a near-critical nonconserved order parameter and quadrupole Raman response in Fe-based superconductors

Cornell Affiliated Author(s)
Author
A. Klein
S. Lederer
Debanjan Chowdhury
E. Berg
A.V. Chubukov
Abstract

We analyze the dynamical response of a two-dimensional system of itinerant fermions coupled to a scalar boson φ, which undergoes a continuous transition towards nematic order with a d-wave form factor. We consider two cases: (a) when φ is a soft collective mode of fermions near a Pomeranchuk instability, and (b) when it is an independent critical degree of freedom, such as a composite spin order parameter. In both cases, the order parameter is not a conserved quantity and the d-wave fermionic polarization Π(q,Ω) remains finite even at q=0.

Journal
Physical Review B
Date Published
Funding Source
1125915
DE-SC0014402
PHY-1125915
PHY-1607611
Group (Lab)
Debanjan Chowdhury Group