Skip to main content

Publications

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

Strong variation of spin-orbit torques with relative spin relaxation rates in ferrimagnets

Cornell Affiliated Author(s)
Author
Lijun Zhu
Daniel Ralph
Abstract

Spin-orbit torques (SOTs) have been widely understood as an interfacial transfer of spin that is independent of the bulk properties of the magnetic layer. Here, we report that SOTs acting on ferrimagnetic FexTb1-x layers decrease and vanish upon approaching the magnetic compensation point because the rate of spin transfer to the magnetization becomes much slower than the rate of spin relaxation into the crystal lattice due to spin-orbit scattering.

Journal
Springer Science and Business Media LLC
Date Published
Funding Source
NNCI-2025233
DMR-1719875
12274405
XDB44000000
2022YFA1200094

Collective density fluctuations of strange metals with critical Fermi surfaces

Cornell Affiliated Author(s)
Author
X. Wang
Debanjan Chowdhury
Abstract

Recent spectroscopic measurements in a number of strongly correlated metals that exhibit non-Fermi-liquid-like properties have observed evidence of anomalous frequency and momentum-dependent charge-density fluctuations. Specifically, in the strange metallic regime of the cuprate superconductors, there is a featureless particle-hole continuum exhibiting unusual power laws, and experiments suggest that the plasmon mode decays into this continuum in a manner that is distinct from the expectations of conventional Fermi liquid theory.

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

Visualizing the atomic-scale origin of metallic behavior in Kondo insulators

Cornell Affiliated Author(s)
Author
H. Pirie
E. Mascot
C.E. Matt
Y. Liu
P. Chen
M.H. Hamidian
S. Saha
X. Wang
J. Paglione
G. Luke
D. Goldhaber-Gordon
C.F. Hirjibehedin
J.C.S. Davis
D.K. Morr
J.E. Hoffman
Abstract

A Kondo lattice is often electrically insulating at low temperatures. However, several recent experiments have detected signatures of bulk metallicity within this Kondo insulating phase. In this study, we visualized the real-space charge landscape within a Kondo lattice with atomic resolution using a scanning tunneling microscope.

Journal
Science
Date Published
Group (Lab)
J.C. Seamus Davis Group

Diamagnetic response and phase stiffness for interacting isolated narrow bands

Cornell Affiliated Author(s)
Author
D. Mao
Debanjan Chowdhury
Abstract

Superconductivity is a macroscopic manifestation of a quantum phenomenon where pairs of electrons delocalize and develop phase coherence over a long distance. A long-standing quest has been to address the underlying microscopic mechanisms that fundamentally limit the superconducting transition temperature, Tc . A platform which serves as an ideal playground for realizing "high"-temperature superconductors are materials where the electrons' kinetic energy is quenched and interactions provide the only energy scale in the problem.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Funding Source
PHY-1607611
Group (Lab)
Debanjan Chowdhury Group

Intrinsic spin Hall torque in a moiré Chern magnet

Cornell Affiliated Author(s)
Author
C.L. Tschirhart
E. Redekop
L. Li
T. Li
S. Jiang
T. Arp
O. Sheekey
T. Taniguchi
K. Watanabe
M.E. Huber
K.F. Mak
J. Shan
A.F. Young
Abstract

In spin torque magnetic memories, electrically actuated spin currents are used to switch a magnetic bit. Typically, these require a multilayer geometry including both a free ferromagnetic layer and a second layer providing spin injection. For example, spin may be injected by a non-magnetic layer exhibiting a large spin Hall effect, a phenomenon known as spin–orbit torque. Here we demonstrate a spin–orbit torque magnetic bit in a single two-dimensional system with intrinsic magnetism and strong Berry curvature.

Journal
Nature Physics
Date Published
Funding Source
DMR-1906325
FA9550-19-1-0390
W911NF-20-2-0166
GBMF9471
1650114
19H05790
20H00354
21H05233
Group (Lab)
Jie Shan Group
Kin Fai Mak Group