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Publications

Interfacial engineering of a ZnO electron transporting layer using self-Assembled monolayers for high performance and stable perovskite solar cells

Cornell Affiliated Author(s)
Author
J. Han
H. Kwon
Eun-Ah Kim
D.-W. Kim
H.J. Son
D.H. Kim
Abstract

We developed perovskite solar cells (PSCs) with a ZnO electron-Transporting layer (ETL) of which the surface was passivated with methoxybenzoic acid self-Assembled monolayers (SAMs). The self-Assembled monolayer (SAM) simultaneously improved the photovoltaic performance and device stability.

Journal
Journal of Materials Chemistry A
Date Published
Funding Source
20173010013340
2015M1A2A2058365
2017R1A2A1A05022387
Group (Lab)

Magneto-Memristive Switching in a 2D Layer Antiferromagnet

Cornell Affiliated Author(s)
Author
H.H. Kim
S. Jiang
B. Yang
S. Zhong
S. Tian
C. Li
H. Lei
J. Shan
K.F. Mak
A.W. Tsen
Abstract

Memristive devices whose resistance can be hysteretically switched by electric field or current are intensely pursued both for fundamental interest as well as potential applications in neuromorphic computing and phase-change memory. When the underlying material exhibits additional charge or spin order, the resistive states can be directly coupled, further allowing electrical control of the collective phases. The observation of abrupt, memristive switching of tunneling current in nanoscale junctions of ultrathin CrI3, a natural layer antiferromagnet, is reported here.

Journal
Advanced Materials
Date Published
Funding Source
2016YFA0300504
ER17-13-199
W911NF-19-10267
N00014-18-1-2368
1807810
FA9550-18-1-0480
11574394
11774423
11822412
NRF-2017K1A3A1A12073407
15XNLQ07
18XNLG14
19XNLG17
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Why Traditional Labs Fail, and What We Can Do About It

Cornell Affiliated Author(s)
Author
N.G. Holmes
Abstract

Science is, at its core, an empirical discipline: Theories must coordinate with evidence obtained through systematic, scientific investigations. Learning science involves learning how science is done, not just what science has found, and so nearly every introductory college science course has an associated laboratory component. The value of these labs, however, has often been called into question, particularly when considering concerns about the associated space, time, equipment, and personnel needs.

Journal
Active Learning in College Science: The Case for Evidence-Based Practice
Date Published
Group (Lab)
Natasha Holmes Group

Role of correlations in determining the Van Hove strain in Sr2 RuO4

Cornell Affiliated Author(s)
Author
Mark Barber
Frank Lechermann
Sergey Streltsov
Sergey Skornyakov
Sayak Ghosh
B. Ramshaw
Naoki Kikugawa
Dmitry Sokolov
Andrew Mackenzie
Clifford Hicks
I. Mazin
Abstract

Uniaxial pressure applied along a Ru-O-Ru bond direction induces an elliptical distortion of the largest Fermi surface of Sr2RuO4, eventually causing a Fermi surface topological transition, also known as a Lifshitz transition, into an open Fermi surface. There are various anomalies in low-temperature properties associated with this transition, including maxima in the superconducting critical temperature and in resistivity.

Journal
Physical Review B
Date Published
Funding Source
1752784
JP18K04715
02.
AAAA-A18-118020190095-4
Group (Lab)
Brad Ramshaw Group

Imaging uncompensated moments and exchange-biased emergent ferromagnetism in FeRh thin films

Cornell Affiliated Author(s)
Author
Isaiah Gray
Gregory Stiehl
John Heron
Antonio Mei
Darrell Schlom
Ramamoorthy Ramesh
Daniel Ralph
Gregory Fuchs
Abstract

Uncompensated moments (UMs) in antiferromagnets are responsible for exchange bias in antiferromagnet/ ferromagnet heterostructures; however, they are difficult to directly detect because any signal they contribute is typically overwhelmed by the ferromagnetic layer. We use magnetothermal microscopy to image micron-scale uncompensated moments in thin films of FeRh, a room-temperature antiferromagnet that exhibits a first-order phase transition to a ferromagnetic (FM) state near 400 K.

Journal
American Physical Society (APS)
Date Published
Funding Source
1542081
1708499
1719875
1740136
SRC

Fractionalized pair density wave in the pseudogap phase of cuprate superconductors

Cornell Affiliated Author(s)
Author
D. Chakraborty
M. Grandadam
M.H. Hamidian
J.C.S. Davis
Y. Sidis
C. Pépin
Abstract

The mysterious pseudogap (PG) phase of cuprate superconductors has been the subject of intense investigation over the last 30 years, but without a clear agreement about its origin. Owing to a recent observation in Raman spectroscopy, of a precursor in the charge channel, on top of the well known fact of a precursor in the superconducting channel, we present here a novel idea: The PG is formed through a Higgs mechanism, where two kinds of preformed pairs, in the particle-particle and particle-hole channels, become entangled through a freezing of their global phase.

Journal
Physical Review B
Date Published
Group (Lab)
J.C. Seamus Davis Group

Magnetic handshake materials as a scale-invariant platform for programmed self-assembly

Cornell Affiliated Author(s)
Author
R. Niu
C.X. Du
E. Esposito
J. Ng
M.P. Brenner
P.L. McEuen
Itai Cohen
Abstract

Programmable self-assembly of smart, digital, and structurally complex materials from simple components at size scales from the macro to the nano remains a long-standing goal of material science. Here, we introduce a platform based on magnetic encoding of information to drive programmable self-assembly that works across length scales. Our building blocks consist of panels with different patterns of magnetic dipoles that are capable of specific binding.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Funding Source
DMR-1435829
N00014-17-1-3029
1435829
ARL FA8650-19-1-7914
DMR-1719875
Research Area
Group (Lab)
Itai Cohen Group
Paul McEuen Group

A New method for computing particle collisions in Navier-Stokes flows

Cornell Affiliated Author(s)
Author
A.E. Yacoubi
S. Xu
Z.J. Wang
Abstract

Particle collisions in fluids are ubiquitous, but to compute the collision dynamics in a Navier-Stokes flow remains challenging. In addition to capturing the two-way coupling between the fluid and the particles, a key difficulty is to resolve the collision dynamics mediated by the flow. The gap between particles during collision is minuscule. This introduces a small length scale which needs to be resolved simultaneously with the flow at the large scale.

Journal
Journal of Computational Physics
Date Published
Funding Source
1320317
Group (Lab)
Z. Jane Wang Group

Dirac fermions and possible weak antilocalization in LaCuSb2

Cornell Affiliated Author(s)
Author
J. Chamorro
A. Topp
Y. Fang
M.J. Winiarski
C.R. Ast
M. Krivenkov
A. Varykhalov
B.J. Ramshaw
L.M. Schoop
T.M. McQueen
Abstract

Layered heavy-metal square-lattice compounds have recently emerged as potential Dirac fermion materials due to bonding within those sublattices. We report quantum transport and spectroscopic data on the layered Sb square-lattice material LaCuSb2. Linearly dispersing band crossings, necessary to generate Dirac fermions, are experimentally observed in the electronic band structure observed using angle-resolved photoemission spectroscopy, along with a quasi-two-dimensional Fermi surface.

Journal
APL Materials
Date Published
Funding Source
1420541
1752784
DMR-1420541
Group (Lab)
Brad Ramshaw Group