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Publications

Preliminary characterization of a laser-generated plasma sheet

Cornell Affiliated Author(s)
Author
P.A. Keiter
G. Malamud
M. Trantham
J. Fein
J. Davis
S.R. Klein
R.P. Drake
Abstract

We present the results from recent experiments to create a flowing plasma sheet. Two groups of three laser beams with nominally 1.5 kJ of energy per group were focused to separate pointing locations, driving a shock into a wedge target. As the shock breaks out of the wedge, the plasma is focused on center, creating a sheet of plasma. Measurements at 60 ns indicate the plasma sheet has propagated 2825 microns with an average velocity of 49 microns/ns. These experiments follow previous experiments [Krauland et al.

Journal
High Energy Density Physics
Date Published
Group (Lab)
J.C. Seamus Davis Group

Evidence for superconductivity in Li-decorated monolayer graphene

Cornell Affiliated Author(s)
Author
B.M. Ludbrook
G. Levy
P. Nigge
M. Zonno
M. Schneider
D.J. Dvorak
C.N. Veenstra
S. Zhdanovich
D. Wong
P. Dosanjh
C. Straßer
A. Stöhr
S. Forti
C.R. Ast
U. Starke
A. Damascelli
J.C. Davis
Abstract

Monolayer graphene exhibits many spectacular electronic properties, with superconductivity being arguably the most notable exception. It was theoretically proposed that superconductivity might be induced by enhancing the electron-phonon coupling through the decoration of graphene with an alkali adatom superlattice [Profeta G, Calandra M, Mauri F (2012) Nat Phys 8(2): 131-134]. Although experiments have shown an adatom-induced enhancement of the electron-phonon coupling, superconductivity has never been observed.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group

Supercooled spin liquid state in the frustrated pyrochlore Dy2Ti2O7

Cornell Affiliated Author(s)
Author
E.R. Kassner
A.B. Eyvazov
B. Pichler
T.J.S. Munsie
H.A. Dabkowska
G.M. Luke
J.C.S. Davis
Abstract

A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific identifiers including microscopic relaxation times diverging on a Vogel-Tammann-Fulcher (VTF) trajectory, a Havriliak-Negami (HN) form for the dielectric function ε(ω, T), and a general Kohlrausch-Williams-Watts (KWW) form for time-domain relaxation.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group

Imaging Dirac-mass disorder from magnetic dopant atoms in the ferromagnetic topological insulator Crx(Bi0.1Sb0.9)2-xTe3

Cornell Affiliated Author(s)
Author
I. Lee
C.K. Kim
J. Lee
S.J.L. Billinge
R. Zhong
J.A. Schneeloch
T. Liu
T. Valla
J.M. Tranquada
G. Gu
J.C.S. Davis
Abstract

To achieve and use the most exotic electronic phenomena predicted for the surface states of 3D topological insulators (TIs), it is necessary to open a "Dirac-mass gap" in their spectrum by breaking timereversal symmetry. Use of magnetic dopant atoms to generate a ferromagnetic state is the most widely applied approach. However, it is unknown how the spatial arrangements of the magnetic dopant atoms influence the Dirac-mass gap at the atomic scale or, conversely, whether the ferromagnetic interactions between dopant atoms are influenced by the topological surface states.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group

Identifying the 'fingerprint' of antiferromagnetic spin fluctuations in iron pnictide superconductors

Cornell Affiliated Author(s)
Author
M.P. Allan
K. Lee
A.W. Rost
M.H. Fischer
F. Massee
K. Kihou
C.-H. Lee
A. Iyo
H. Eisaki
T.-M. Chuang
J.C. Davis
Eun-Ah Kim
Abstract

Cooper pairing in the iron-based high-T c superconductors is often conjectured to involve bosonic fluctuations. Among the candidates are antiferromagnetic spin fluctuations and d-orbital fluctuations amplified by phonons. Any such electron-boson interaction should alter the electron's 'self-energy', and then become detectable through consequent modifications in the energy dependence of the electron's momentum and lifetime.

Journal
Nature Physics
Date Published
Funding Source
DE-SC0010313
DE-2009-BNL-PM015
DMR-0955822
DMR-1120296
0520404
22540380
EP/I031014/1
24340090
NSC101-2112-M-001-029-MY3
Group (Lab)
J.C. Seamus Davis Group

Spectroscopic Imaging STM: Atomic-Scale Visualization of Electronic Structure and Symmetry in Underdoped Cuprates

Cornell Affiliated Author(s)
Author
K. Fujita
M. Hamidian
I. Firmo
S. Mukhopadhyay
C.K. Kim
H. Eisaki
S.-I. Uchida
J.C. Davis
Abstract

Atomically resolved spectroscopic imaging STM (SI-STM) has played a pivotal role in visualization of the electronic structure of cuprate high temperature superconductors. In both the d-wave superconducting (dSC) and the pseudogap (PG) phases of underdoped cuprates, two distinct types of electronic states are observed when using SI-STM.

Journal
Springer Series in Solid-State Sciences
Date Published
Group (Lab)
J.C. Seamus Davis Group

Direct evidence for a magnetic f-electron-mediated pairing mechanism of heavy-fermion superconductivity in CeCoIn5

Cornell Affiliated Author(s)
Author
J.S. Van Dyke
F. Massee
M.P. Allan
J.C.S. Davis
C. Petrovic
D.K. Morr
Abstract

To identify the microscopic mechanism of heavy-fermion Cooper pairing is an unresolved challenge in quantum matter studies; it may also relate closely to finding the pairing mechanism of hightemperature superconductivity. Magnetically mediated Cooper pairing has long been the conjectured basis of heavy-fermion superconductivity but no direct verification of this hypothesis was achievable.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group

Direct phase-sensitive identification of a d-form factor density wave in underdoped cuprates

Cornell Affiliated Author(s)
Author
K. Fujita
M.H. Hamidian
S.D. Edkins
C.K. Kim
Y. Kohsaka
M. Azuma
M. Takano
H. Takagi
H. Eisaki
S.-I. Uchida
A. Allais
M.J. Lawler
Eun-Ah Kim
S. Sachdev
J.C. Davis
Abstract

The identity of the fundamental broken symmetry (if any) in the underdoped cuprates is unresolved. However, evidence has been accumulating that this state may be an unconventional density wave. Here we carry out site-specific measurements within each CuO2 unit cell, segregating the results into three separate electronic structure images containing only the Cu sites [Cu(r)] and only the x/y axis O sites [Ox (r) and Oy( r)]. Phase-resolved Fourier analysis reveals directly that the modulations in the Ox(r) and Oy(r) sublattice images consistently exhibit a relative phase of π.

Journal
Proceedings of the National Academy of Sciences of the United States of America
Date Published
Group (Lab)
J.C. Seamus Davis Group
Michael Lawler Group

Simultaneous transitions in cuprate momentum-space topology and electronic symmetry breaking

Cornell Affiliated Author(s)
Author
K. Fujita
C.K. Kim
I. Lee
J. Lee
M.H. Hamidian
I.A. Firmo
S. Mukhopadhyay
H. Eisaki
S. Uchida
M.J. Lawler
Eun-Ah Kim
J.C. Davis
Abstract

The existence of electronic symmetry breaking in the underdoped cuprates and its disappearance with increased hole density p are now widely reported. However, the relation between this transition and the momentum-space (k →-space) electronic structure underpinning the superconductivity has not yet been established. Here, we visualize the Q→ = 0 (intra-unit-cell) and Q→ ≠ 0 (density-wave) broken-symmetry states, simultaneously with the coherent k→-space topology, for Bi2Sr2CaCu2O8+δ samples spanning the phase diagram 0.06 ≤ p ≤ 0.23.

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