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Publications

Observation of site-controlled localized charged excitons in CrI3/WSe2 heterostructures

Cornell Affiliated Author(s)
Author
A. Mukherjee
K. Shayan
L. Li
J. Shan
K.F. Mak
A.N. Vamivakas
Abstract

Isolated spins are the focus of intense scientific exploration due to their potential role as qubits for quantum information science. Optical access to single spins, demonstrated in III-V semiconducting quantum dots, has fueled research aimed at realizing quantum networks. More recently, quantum emitters in atomically thin materials such as tungsten diselenide have been demonstrated to host optically addressable single spins by means of electrostatic doping the localized excitons.

Journal
Nature Communications
Date Published
Funding Source
1553788
MRSEC-DMR-1719875
D43TW010074
FA9550-19-1-0074
DE-SC0019481
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Opposite Polarity Surface Photovoltage of MoS2Monolayers on Au Nanodot versus Nanohole Arrays

Cornell Affiliated Author(s)
Author
J. Song
S. Kwon
B. Kim
Eun-Ah Kim
L.N.S. Murthy
T. Lee
I. Hong
B.H. Lee
S.W. Lee
S.H. Choi
K.K. Kim
C.-H. Cho
J.W.P. Hsu
D.-W. Kim
Abstract

We prepared MoS2 monolayers on Au nanodot (ND) and nanohole (NH) arrays. Both these sample arrays exhibited enhanced photoluminescence intensity compared with that of a bare SiO2/Si substrate. The reflectance spectra of MoS2/ND and MoS2/NH had clear features originating from excitation of localized surface plasmon and propagating surface plasmon polaritons. Notably, the surface photovoltages (SPV) of these hybrid plasmonic nanostructures had opposite polarities, indicating negative and positive charging at MoS2/ND and MoS2/NH, respectively.

Journal
ACS Applied Materials and Interfaces
Date Published
Group (Lab)

Inhomogeneous ferromagnetism mimics signatures of the topological Hall effect in SrRuO3 films

Cornell Affiliated Author(s)
Author
G. Kim
K. Son
Y.E. Suyolcu
L. Miao
N.J. Schreiber
H.P. Nair
D. Putzky
M. Minola
G. Christiani
P.A. Van Aken
K.M. Shen
D.G. Schlom
G. Logvenov
B. Keimer
Abstract

Topological transport phenomena in magnetic materials are a major topic of current condensed matter research. One of the most widely studied phenomena is the topological Hall effect (THE), which is generated via spin-orbit interactions between conduction electrons and topological spin textures such as skyrmions. We report a comprehensive set of Hall effect and magnetization measurements on epitaxial films of the prototypical ferromagnetic metal SrRuO3 the magnetic and transport properties of which were systematically modulated by varying the concentration of Ru vacancies.

Journal
Physical Review Materials
Date Published
Funding Source
DMR-1539918
DGE-1650441
GBMF3850
GBMF9073
669550
823717
Group (Lab)
Kyle Shen Group

The Ground State Electronic Energy of Benzene

Cornell Affiliated Author(s)
Author
Janus Eriksen
Tyler Anderson
Emiliano Deustua
Khaldoon Ghanem
Diptarka Hait
Mark Hoffmann
Seunghoon Lee
Daniel Levine
Ilias Magoulas
Jun Shen
Norm Tubman
Birgitta Whaley
Enhua Xu
Yuan Yao
Ning Zhang
Ali Alavi
Garnet Chan
Martin Head-Gordon
Wenjian Liu
Piotr Piecuch
Sandeep Sharma
Seiichiro Ten-no
C. Umrigar
Jürgen Gauss
Abstract

We report on the findings of a blind challenge devoted to determining the frozen-core, full configuration interaction (FCI) ground-state energy of the benzene molecule in a standard correlation-consistent basis set of double-ζ quality. As a broad international endeavor, our suite of wave function-based correlation methods collectively represents a diverse view of the high-accuracy repertoire offered by modern electronic structure theory.

Journal
Journal of Physical Chemistry Letters
Date Published
Funding Source
ACI-1445606
ACI-1547580
1665333
CHE-1800584
DE-AC02-05CH11231
FA9550-18-1-0095
DE-FG02-01ER15228
JP18H03900
21033001
21973054
Group (Lab)
Cyrus Umrigar Group

Manipulation of the van der Waals Magnet Cr2Ge2Te6 by Spin–Orbit Torques

Author
Vishakha Gupta
Thow Cham
Gregory Stiehl
Arnab Bose
Joseph Mittelstaedt
Kaifei Kang
Shengwei Jiang
Kin Mak
Jie Shan
Robert Buhrman
Daniel Ralph
Abstract

We report measurements of current-induced thermoelectric and spin-orbit torque effects within devices in which multilayers of the semiconducting two-dimensional van der Waals magnet Cr2Ge2Te6 (CGT) are integrated with Pt and Ta metal overlayers. We show that the magnetic orientation of the CGT can be detected accurately either electrically (using an anomalous Hall effect) or optically (using magnetic circular dichroism) with good consistency.

Journal
American Chemical Society (ACS)
Date Published
Funding Source
1719875
2776.047
DMR-1719875
N00014-18-1-2368
NNCI-2025233
DE-SC0017671
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Direct Visualization of Trimerized States in 1T−TaTe2

Cornell Affiliated Author(s)
Author
Ismail Baggari
Nikhil Sivadas
Gregory Stiehl
Jacob Waelder
Daniel Ralph
Craig Fennie
Lena Kourkoutis
Abstract

Transition-metal dichalcogenides containing tellurium anions show remarkable charge-lattice modulated structures and prominent interlayer character. Using cryogenic scanning transmission electron microscopy (STEM), we map the atomic-scale structures of the high temperature (HT) and low temperature (LT) modulated phases in 1T'-TaTe2. At HT, we directly show in-plane metal distortions which form trimerized clusters and staggered, three-layer stacking.

Journal
American Physical Society (APS)
Date Published
Funding Source
DMR-1539918
DE-SC0017671
NSF-MRI-1429155
1719875
DMR-1719875

Electrical switching of valley polarization in monolayer semiconductors

Cornell Affiliated Author(s)
Author
L. Li
S. Jiang
Z. Wang
K. Watanabe
T. Taniguchi
J. Shan
K.F. Mak
Abstract

Achieving on-demand control of the valley degree of freedom is essential for valley-based information science and technology. Optical and magnetic control of the valley degree of freedom in monolayer transition-metal dichalcogenide (TMD) semiconductors has been studied extensively. However, electrical control of the valley polarization has remained a challenge. Here we demonstrate switching of the valley polarization in monolayer WSe2 by electrical gating. This is achieved by coupling a WSe2 monolayer to a two-dimensional (2D) layered magnetic insulator CrI3.

Journal
Physical Review Materials
Date Published
Funding Source
DMR-1807810
FA9550-18-1-0480
DMR-1719875
JPMJCR15F3
Group (Lab)
Jie Shan Group
Kin Fai Mak Group

Establishing strongly-coupled 3D AdS quantum gravity with Ising dual using all-genus partition functions

Cornell Affiliated Author(s)
Author
Chao-Ming Jian
Andreas Ludwig
Zhu-Xi Luo
Hao-Yu Sun
Zhenghan Wang
Abstract

Abstract We study 3D pure Einstein quantum gravity with negative cosmological constant, in the regime where the AdS radius l is of the order of the Planck scale. Specifically, when the Brown-Henneaux central charge c = 3l/2GN (GN is the 3D Newton constant) equals c = 1/2, we establish duality between 3D gravity and 2D Ising conformal field theory by matching gravity and conformal field theory partition functions for AdS spacetimes with general asymptotic boundaries. This duality was suggested by a genus-one calculation of Castro et al. [Phys. Rev. D85 (2012) 024032].

Journal
Journal of High Energy Physics
Date Published
Funding Source
1309667
1748958
Group (Lab)
Chao-Ming Jian Group

Fabrication of Injectable Micro-Scale Opto- Electronically Transduced Electrodes (MOTEs) for Physiological Monitoring

Cornell Affiliated Author(s)
Author
S. Lee
A.J. Cortese
A. Mok
C. Wu
T. Wang
J.U. Park
C. Smart
S. Ghajari
D. Khilwani
S. Sadeghi
Y. Ji
J.H. Goldberg
C. Xu
P.L. McEuen
A.C. Molnar
Abstract

In vivo, chronic neural recording is critical to understand the nervous system, while a tetherless, miniaturized recording unit can render such recording minimally invasive. We present a tetherless, injectable micro-scale opto-electronically transduced electrode (MOTE) that is ∼ 60μ m × 30μ m × 330μ m, the smallest neural recording unit to date. The MOTE consists of an AlGaAs micro-scale light emitting diode (μ LED) heterogeneously integrated on top of conventional 180nm complementary metal-oxide-semiconductor (CMOS) circuit.

Journal
Journal of Microelectromechanical Systems
Date Published
Funding Source
DMR-1120296
ECCS-1542081
R21-EY027581
U01-NS107687
Group (Lab)
Paul McEuen Group

The 2021 quantum materials roadmap

Cornell Affiliated Author(s)
Author
F. Giustino
J.H. Lee
F. Trier
M. Bibes
S.M. Winter
R. Valentí
Y.-W. Son
L. Taillefer
C. Heil
A.I. Figueroa
B. Plaçais
Q. Wu
O.V. Yazyev
E.P.A.M. Bakkers
J. Nygård
P. Forn-Díaz
S. de Franceschi
J.W. McIver
L.E.F. Torres
T. Low
A. Kumar
R. Galceran
S.O. Valenzuela
M.V. Costache
A. Manchon
Eun-Ah Kim
G.R. Schleder
A. Fazzio
S. Roche
Abstract

In recent years, the notion of ‘Quantum Materials’ has emerged as a powerful unifying concept across diverse fields of science and engineering, from condensed-matter and coldatom physics to materials science and quantum computing.

Journal
JPhys Materials
Date Published
Group (Lab)