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Publications

Non-equilibrium ordering of liquid crystalline (LC) films driven by external gradients in surfactant concentration

Cornell Affiliated Author(s)
Author
S. Maiti
S. Roh
Itai Cohen
N.L. Abbott
Abstract

Hypothesis: Gradients in the concentration of amphiphiles play an important role in many non-equilibrium processes involving complex fluids. Here we explore if non-equilibrium interfacial behaviors of thermotropic (oily) liquid crystals (LCs) can amplify microscopic gradients in surfactant concentration into macroscopic optical signals. Experiments: We use a milli-fluidic system to generate gradients in aqueous sodium dodecyl sulfate (SDS) concentration and optically quantify the dynamic ordering of micrometer-thick nematic LC films that contact the gradients.

Journal
Journal of Colloid and Interface Science
Date Published
Funding Source
CBET-1803409
EFMA1935252
NNCI-2025233
W911NF-15-1-0568
W911NF-17-1-0575
Group (Lab)
Itai Cohen Group

Synthesis, Hole Doping, and Electrical Properties of a Semiconducting Azatriangulene-Based Covalent Organic Framework

Cornell Affiliated Author(s)
Author
David Burke
Raghunath Dasari
Vinod Sangwan
Alexander Oanta
Zoheb Hirani
Chloe Pelkowski
Yongjian Tang
Ruofan Li
Daniel Ralph
Mark Hersam
Stephen Barlow
Seth Marder
William Dichtel
Journal
Journal of the American Chemical Society
Date Published
Funding Source
W911NF-15-1-0447
DGE-1842165
NSF ECCS-2025633
NSF ECCS-2025633
NSF DMR-1720139
NSF DMR-1720139
DE-SC0017671
NNCI-2025233
DE-AC02-06CH11357
DE-SC0012704

Switchable moiré potentials in ferroelectric WTe2/WSe2 superlattices

Cornell Affiliated Author(s)
Author
K. Kang
W. Zhao
Y. Zeng
K. Watanabe
T. Taniguchi
J. Shan
K.F. Mak
Abstract

Moiré materials with superlattice periodicity many times the atomic length scale have shown strong electronic correlations and band topology with unprecedented tunability. Non-volatile control of the moiré potentials could allow on-demand switching of superlattice effects but has remained challenging to achieve. Here we demonstrate the switching of the correlated and moiré band insulating states, and the associated nonlinear anomalous Hall effect, by the ferroelectric effect.

Journal
Nature Nanotechnology
Date Published
Funding Source
DMR-2039380
FA9550-18-1-0480
DE-SC0019481
DMR-1719875
NNCI-2025233
JPMJCR15F3
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

A puzzling insensitivity of magnon spin diffusion to the presence of 180-degree domain walls

Cornell Affiliated Author(s)
Author
Ruofan Li
Lauren Riddiford
Yahong Chai
Minyi Dai
Hai Zhong
Bo Li
Peng Li
Di Yi
Yuejie Zhang
David Broadway
Adrien Dubois
Patrick Maletinsky
Jiamian Hu
Yuri Suzuki
Daniel Ralph
Tianxiang Nan
Abstract

We present room-temperature measurements of magnon spin diffusion in epitaxial ferrimagnetic insulator MgAl0.5Fe1.5O4 (MAFO) thin films near zero applied magnetic field where the sample forms a multi-domain state. Due to a weak uniaxial magnetic anisotropy, the domains are separated primarily by 180° domain walls.

Journal
Springer Science and Business Media LLC
Date Published
Funding Source
N00014-15-1-0045
ACI-1548562
CBET-2006028
NNCI-2025233
FA 9550-20-1-0293
DMR-1719875
52161135103
2021YFA0716500

Domain-Dependent Surface Adhesion in Twisted Few-Layer Graphene: Platform for Moiré-Assisted Chemistry

Cornell Affiliated Author(s)
Author
V. Hsieh
D. Halbertal
N.R. Finney
Z. Zhu
E. Gerber
M. Pizzochero
E. Kucukbenli
G.R. Schleder
M. Angeli
K. Watanabe
T. Taniguchi
Eun-Ah Kim
E. Kaxiras
J. Hone
C.R. Dean
D.N. Basov
Abstract

Twisted van der Waals multilayers are widely regarded as a rich platform to access novel electronic phases thanks to the multiple degrees of freedom available for controlling their electronic and chemical properties. Here, we propose that the stacking domains that form naturally due to the relative twist between successive layers act as an additional ”knob” for controlling the behavior of these systems and report the emergence and engineering of stacking domain-dependent surface chemistry in twisted few-layer graphene.

Journal
Nano Letters
Date Published
Group (Lab)

High spatial resolution direct conversion amorphous selenium X-ray detectors with monolithically integrated CMOS readout

Cornell Affiliated Author(s)
Author
Z. Han
A. Mukherjee
A. Albert
A.K. Rumaiz
I. Harding
M.W. Tate
S.M. Gruner
J. Thom-Levy
A.J. Kuczewski
D.P. Siddons
G.A. Carini
J. Stavro
S. Léveillé
D. Vasileska
W. Zhao
A. Goldan
Abstract

Recent progress in the field of micron-scale spatial resolution direct conversion X-ray detectors for high-energy synchrotron light sources serve applications ranging from nondestructive and noninvasive microscopy techniques which provide insight into the structure and morphology of crystals, to medical diagnostic measurement devices. Amorphous selenium (a-Se) as a wide-bandgap thermally evaporated photoconductor exhibits ultra-low thermal generation rates for dark carriers and has been extensively used in X-ray medical imaging.

Journal
Journal of Instrumentation
Date Published
Funding Source
DE-SC0020144
DE-SC0017631
PHY-1549132
DE-AC02-76SF00515
Group (Lab)
Sol M. Gruner Group

Superfluid response of an atomically thin gate-tuned van der Waals superconductor

Cornell Affiliated Author(s)
Author
A. Jarjour
G.M. Ferguson
B.T. Schaefer
M. Lee
Y.L. Loh
N. Trivedi
K.C. Nowack
Abstract

A growing number of two-dimensional superconductors are being discovered in the family of exfoliated van der Waals materials. Due to small sample volume, the superfluid response of these materials has not been characterized. Here, we use a local magnetic probe to directly measure this key property of the tunable, gate-induced superconducting state in MoS2. We find that the backgate changes the transition temperature non-monotonically whereas the superfluid stiffness at low temperature and the normal state conductivity monotonically increase.

Journal
Nature Communications
Date Published
Funding Source
DMR-2004864
NNCI-2025233
2138905
DMR-1719875
Group (Lab)
Katja Nowack Group

ATRP Enhances Structural Correlations In Polymerization-Induced Phase Separation**

Cornell Affiliated Author(s)
Author
A. Sicher
R. Whitfield
J. Ilavsky
V. Saranathan
A. Anastasaki
E.R. Dufresne
Abstract

Synthetic methods to control the structure of materials at sub-micron scales are typically based on the self-assembly of structural building blocks with precise size and morphology. On the other hand, many living systems can generate structure across a broad range of length scales in one step directly from macromolecules, using phase separation. Here, we introduce and control structure at the nano- and microscales through polymerization in the solid state, which has the unusual capability of both triggering and arresting phase separation.

Journal
Angewandte Chemie - International Edition
Date Published
Funding Source
DE‐AC02‐06CH11357
Group (Lab)
Eric Dufresne Group

Gate-tunable heavy fermions in a moiré Kondo lattice

Cornell Affiliated Author(s)
Author
W. Zhao
B. Shen
Z. Tao
Z. Han
K. Kang
K. Watanabe
T. Taniguchi
K.F. Mak
J. Shan
Abstract

The Kondo lattice—a matrix of local magnetic moments coupled through spin-exchange interactions to itinerant conduction electrons—is a prototype of strongly correlated quantum matter1–4. Usually, Kondo lattices are realized in intermetallic compounds containing lanthanide or actinide1,2. The complex electronic structure and limited tunability of both the electron density and exchange interactions in these bulk materials pose considerable challenges to studying Kondo lattice physics.

Journal
Nature
Date Published
Funding Source
DMR-2004451
DMR-2039380
NNCI-2025233
FA9550-19-1-0390
DE-SC0019481
DMR-1719875
JPMJCR15F3
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Higher-form Symmetries under Weak Measurement

Cornell Affiliated Author(s)
Author
Kaixiang Su
Nayan Myerson-Jain
Chong Wang
Chao-Ming Jian
Cenke Xu
Abstract

We aim to address the following question: if we start with a quantum state with a spontaneously broken higher-form symmetry, what is the fate of the system under weak local quantum measurements? We demonstrate that under certain conditions, a phase transition can be driven by weak measurements, which suppresses the spontaneous breaking of the 1-form symmetry and weakens the 1-form symmetry charge fluctuation.

Journal
arXiv e-prints
Date Published
Group (Lab)
Chao-Ming Jian Group