|
|
Hari
Padma
,
Filippo
Glerean
,
Sophia F. R.
Tenhuisen
,
Zecheng
Shen
,
Haoxin
Wang
,
Luogen
Xu
,
Joshua D.
Elliott
,
Christopher C.
Homes
,
Elizabeth
Skoropata
,
Hiroki
Ueda
,
Biaolong
Liu
,
Eugenio
Paris
,
Arnau
Romaguera Camps
,
Byungjune
Lee
,
Wei
He
,
Yu
Wang
,
Seng Huat
Lee
,
Hyeongi
Choi
,
Sang-Youn
Park
,
Zhiqiang
Mao
,
Matteo
Calandra
,
Hoyoung
Jang
,
Elia
Razzoli
,
Mark P. M.
Dean
,
Yao
Wang
,
Matteo
Mitrano
Abstract: Optically excited quantum materials exhibit non-equilibrium states with remarkable emergent properties, but these phenomena are usually transient, decaying on picosecond timescales and limiting practical applications. Advancing the design and control of non-equilibrium phases requires the development of targeted strategies to achieve long-lived, metastable phases. Here we report the discovery of symmetry-protected electronic metastability in the model cuprate ladder Sr14Cu24O41. Using femtosecond resonant X-ray scattering and spectroscopy, we show that this metastability is driven by a transfer of holes from chain-like charge reservoirs into the ladders. This ultrafast charge redistribution arises from the optical dressing and activation of a hopping pathway that is forbidden by symmetry at equilibrium. Relaxation back to the ground state is, hence, suppressed after the pump coherence dissipates. Our findings highlight how dressing materials with electromagnetic fields can dynamically activate terms in the electronic Hamiltonian, and provide a rational design strategy for non-equilibrium phases of matter.
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Jun 2025
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Sophia F. R.
Tenhuisen
,
Grace A.
Pan
,
Qi
Song
,
Denitsa R.
Baykusheva
,
Dan
Ferenc Segedin
,
Berit H.
Goodge
,
Hanjong
Paik
,
Jonathan
Pelliciari
,
Valentina
Bisogni
,
Yanhong
Gu
,
Stefano
Agrestini
,
Abhishek
Nag
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Lena F.
Kourkoutis
,
Charles M.
Brooks
,
Julia E. A.
Mundy
,
Mark P. M.
Dean
,
Matteo
Mitrano
Diamond Proposal Number(s):
[27484]
Abstract: Magnetic interactions are thought to play a key role in the properties of many unconventional superconductors, including cuprates, iron pnictides, and square-planar nickelates. Superconductivity was also recently observed in the bilayer and trilayer Ruddlesden-Popper nickelates, the electronic structure of which is expected to differ from that of cuprates and square-planar nickelates. Here we study how electronic structure and magnetic interactions evolve with the number of layers, 𝑛, in thin film Ruddlesden-Popper nickelates Nd𝑛+1Ni𝑛O3𝑛+1 with 𝑛=1,3, and 5 using resonant inelastic x-ray scattering (RIXS). The RIXS spectra are consistent with a high-spin |3𝑑8
𝐿
̲
⟩ electronic configuration, resembling that of La2−𝑥Sr𝑥NiO4 and the parent perovskite, NdNiO3. The magnetic excitations soften to lower energy in the structurally self-doped, higher-𝑛 films. Our observations confirm that structural tuning is an effective route for altering electronic properties, such as magnetic superexchange, in this prominent family of materials.
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Apr 2025
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
X. T.
Li
,
S. J.
Tu
,
L.
Chaix
,
C.
Fawaz
,
M.
D’astuto
,
X.
Li
,
F.
Yakhou-Harris
,
K.
Kummer
,
N. B.
Brookes
,
Mirian
Garcia-Fernandez
,
K.-J.
Zhou
,
Z. F.
Lin
,
J.
Yuan
,
K.
Jin
,
M. P.
Dean
,
X.
Liu
Diamond Proposal Number(s):
[27478]
Abstract: We investigated the high energy spin excitations in electron-doped
La
2
−
x
Ce
x
CuO
4
, a cuprate superconductor, by resonant inelastic x-ray scattering (RIXS) measurements. Efforts were paid to disentangle the paramagnon signal from non-spin-flip spectral weight mixing in the RIXS spectrum at
Q
∥
=
(
0.6
π
,
0
)
and
(
0.9
π
,
0
)
along the (1 0) direction. Our results show that, for doping level
x
from 0.07 to 0.185, the variation of the paramagnon excitation energy is marginal. We discuss the implication of our results in connection with the evolution of the electron correlation strength in this system.
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Feb 2024
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
C. D.
Dashwood
,
A.
Geondzhian
,
J. G.
Vale
,
A. C.
Pakpour-Tabrizi
,
C. A.
Howard
,
Q.
Faure
,
L. S. I.
Veiga
,
D.
Meyers
,
G. S.
Chiuzbaian
,
A.
Nicolaou
,
N.
Jaouen
,
R. B.
Jackman
,
A.
Nag
,
M.
Garcia-Fernandez
,
Ke-Jin
Zhou
,
A. C.
Walters
,
K.
Gilmore
,
D. F.
Mcmorrow
,
M. P. M.
Dean
Diamond Proposal Number(s):
[22695]
Open Access
Abstract: Interactions between electrons and lattice vibrations are responsible for a wide range of material properties and applications. Recently, there has been considerable interest in the development of resonant inelastic x-ray scattering (RIXS) as a tool for measuring electron-phonon (
e
-ph) interactions. Here, we demonstrate the ability of RIXS to probe the interaction between phonons and specific electronic states both near to, and away from, the Fermi level. We perform carbon
K
-edge RIXS measurements on graphite, tuning the incident x-ray energy to separately probe the interactions of the
π
∗
and
σ
∗
electronic states. Our high-resolution data reveal detailed structure in the multiphonon RIXS features that directly encodes the momentum dependence of the
e
-ph interaction strength. We develop a Green’s-function method to model this structure, which naturally accounts for the phonon and interaction-strength dispersions, as well as the mixing of phonon momenta in the intermediate state. This model shows that the differences between the spectra can be fully explained by contrasting trends of the
e
-ph interaction through the Brillouin zone, being concentrated at the
Γ
and
K
points for the
π
∗
states while being significant at all momenta for the
σ
∗
states. Our results advance the interpretation of phonon excitations in RIXS and extend its applicability as a probe of
e
-ph interactions to a new range of out-of-equilibrium situations.
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Dec 2021
|
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
J. Q.
Lin
,
P.
Villar Arribi
,
G.
Fabbris
,
A. S.
Botana
,
D.
Meyers
,
H.
Miao
,
Y.
Shen
,
D. G.
Mazzone
,
J.
Feng
,
G. S.
Chiuzbaian
,
A.
Nag
,
A. C.
Walters
,
M.
Garcia-Fernandez
,
K.-J.
Zhou
,
J.
Pelliciari
,
I.
Jarrige
,
J. W.
Freeland
,
J.
Zhang
,
J. F.
Mitchell
,
V.
Bisogni
,
X.
Liu
,
M. R.
Norman
,
M. P. M.
Dean
Diamond Proposal Number(s):
[18519]
Abstract: The discovery of superconductivity in a
d
9
−
δ
nickelate has inspired disparate theoretical perspectives regarding the essential physics of this class of materials. A key issue is the magnitude of the magnetic superexchange, which relates to whether cuprate-like high-temperature nickelate superconductivity could be realized. We address this question using Ni
L
-edge and O
K
-edge spectroscopy of the reduced
d
9
−
1
/
3
trilayer nickelates
R
4
Ni
3
O
8
(where
R
=
La
, Pr) and associated theoretical modeling. A magnon energy scale of
∼
80
meV
resulting from a nearest-neighbor magnetic exchange of
J
=
69
(
4
)
meV
is observed, proving that
d
9
−
δ
nickelates can host a large superexchange. This value, along with that of the Ni-O hybridization estimated from our O
K
-edge data, implies that trilayer nickelates represent an intermediate case between the infinite-layer nickelates and the cuprates. Layered nickelates thus provide a route to testing the relevance of superexchange to nickelate superconductivity.
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Feb 2021
|
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
J. Q.
Lin
,
H.
Miao
,
D. G.
Mazzone
,
G. D.
Gu
,
A.
Nag
,
A. C.
Walters
,
M.
Garcia-Fernandez
,
A.
Barbour
,
J.
Pelliciari
,
I.
Jarrige
,
M.
Oda
,
K.
Kurosawa
,
N.
Momono
,
K.
Zhou
,
V.
Bisogni
,
X.
Liu
,
M. P. M.
Dean
Diamond Proposal Number(s):
[22261]
Abstract: The discovery of charge-density-wave-related effects in the resonant inelastic x-ray scattering spectra of cuprates holds the tantalizing promise of clarifying the interactions that stabilize the electronic order. Here, we report a comprehensive resonant inelastic x-ray scattering study of
La
2
−
x
Sr
x
CuO
4
finding that charge-density wave effects persist up to a remarkably high doping level of
x
=
0.21
before disappearing at
x
=
0.25
. The inelastic excitation spectra remain essentially unchanged with doping despite crossing a topological transition in the Fermi surface. This indicates that the spectra contain little or no direct coupling to electronic excitations near the Fermi surface, rather they are dominated by the resonant cross section for phonons and charge-density-wave-induced phonon softening. We interpret our results in terms of a charge-density wave that is generated by strong correlations and a phonon response that is driven by the charge-density-wave-induced modification of the lattice.
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May 2020
|
|
I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Jiaqi
Lin
,
Jie
Yuan
,
Kui
Jin
,
Zhiping
Yin
,
Gang
Li
,
Ke-Jin
Zhou
,
Xingye
Lu
,
Marcus
Dantz
,
Thorsten
Schmitt
,
Hong
Ding
,
Haizhong
Guo
,
Mark P. M.
Dean
,
Xuerong
Liu
Open Access
Abstract: Electron correlations play a dominant role in the charge dynamics of the cuprates. We use resonant inelastic X-ray scattering (RIXS) to track the doping dependence of the collective charge excitations in electron doped La
2−x
2−x
Ce
x
x
CuO
4
4
(LCCO). From the resonant energy dependence and the out-of-plane momentum dependence, the charge excitations are identified as three-dimensional (3D) plasmons, which reflect the nature of the electronic structure and Coulomb repulsion on both short and long lengthscales. With increasing electron doping, the plasmon excitations increase monotonically in energy, a consequence of the electron correlation effect on electron structure near the Fermi surface (FS). Importantly, the plasmon excitations evolve from a broad feature into a well-defined peak with much increased life time, revealing the evolution of the electrons from incoherent states to coherent quasi-particles near the FS. Such evolution marks the reduction of the short-range electronic correlation, and thus the softening of the Mottness of the system with increasing electron doping.
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Jan 2020
|
|
|
|
D.
Meyers
,
H.
Miao
,
A.
Walters
,
V.
Bisogni
,
R. S.
Springell
,
M.
D'Astuto
,
M.
Dantz
,
J.
Pelliciari
,
H. Y.
Huang
,
J.
Okamoto
,
D. J.
Huang
,
J. P.
Hill
,
X.
He
,
I.
Božović
,
T.
Schmitt
,
M. P. M.
Dean
Abstract: The magnetic correlations within the cuprates have undergone intense scrutiny as part of efforts to understand high-temperature superconductivity. We explore the evolution of the magnetic correlations along the nodal direction of the Brillouin zone in
La
2
−
x
Sr
x
CuO
4
, spanning the doping phase diagram from the antiferromagnetic Mott insulator at
x
=
0
to the metallic phase at
x
=
0.26
. Magnetic excitations along this direction are found to be systematically softened and broadened with doping, at a higher rate than the excitations along the antinodal direction. This phenomenology is discussed in terms of the nature of the magnetism in the doped cuprates. Survival of the high-energy magnetic excitations, even in the overdoped regime, indicates that these excitations are marginal to pairing, while the influence of the low-energy excitations remains ambiguous.
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Feb 2017
|
|
I10-Beamline for Advanced Dichroism - scattering
|
Jason D.
Hoffman
,
Brian J.
Kirby
,
Jihwan
Kwon
,
Gilberto
Fabbris
,
D.
Meyers
,
John W.
Freeland
,
Ivar
Martin
,
Olle G.
Heinonen
,
Paul
Steadman
,
Hua
Zhou
,
Christian M.
Schlepütz
,
Mark P. m.
Dean
,
Suzanne G. e.
Te Velthuis
,
Jian-Min
Zuo
,
Anand
Bhattacharya
Diamond Proposal Number(s):
[9626]
Open Access
Abstract: Interfaces between correlated complex oxides are promising avenues to realize new forms of magnetism that arise as a result of charge transfer, proximity effects, and locally broken symmetries. We report on the discovery of a noncollinear magnetic structure in superlattices of the ferromagnetic metallic oxide La2/3Sr1/3MnO3 (LSMO) and the correlated metal LaNiO3 (LNO). The exchange interaction between LSMO layers is mediated by the intervening LNO, such that the angle between the magnetization of neighboring LSMO layers varies in an oscillatory manner with the thickness of the LNO layer. The magnetic field, temperature, and spacer thickness dependence of the noncollinear structure are inconsistent with the bilinear and biquadratic interactions that are used to model the magnetic structure in conventional metallic multilayers. A model that couples the LSMO layers to a helical spin state within the LNO fits the observed behavior. We propose that the spin-helix results from the interaction between a spatially varying spin susceptibility within the LNO and interfacial charge transfer that creates localized Ni2+ states. Our work suggests a new approach to engineering noncollinear spin textures in metallic oxide heterostructures.
|
Nov 2016
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