I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Qiang
Gao
,
Shiyu
Fan
,
Qisi
Wang
,
Jiarui
Li
,
Xiaolin
Ren
,
Izabela
Bialo
,
Annabella
Drewanowski
,
Pascal
Rothenbühler
,
Jaewon
Choi
,
Ronny
Sutarto
,
Yao
Wang
,
Tao
Xiang
,
Jiangping
Hu
,
Ke-Jin
Zhou
,
Valentina
Bisogni
,
Riccardo
Comin
,
Johan
Chang
,
Jonathan
Pelliciari
,
Xingjiang
Zhou
,
Zhihai
Zhu
Diamond Proposal Number(s):
[30189]
Open Access
Abstract: Strongly correlated materials respond sensitively to external perturbations such as strain, pressure, and doping. In the recently discovered superconducting infinite-layer nickelates, the superconducting transition temperature can be enhanced via only ~ 1% compressive strain-tuning with the root of such enhancement still being elusive. Using resonant inelastic x-ray scattering (RIXS), we investigate the magnetic excitations in infinite-layer PrNiO2 thin films grown on two different substrates, namely SrTiO3 (STO) and (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) enforcing different strain on the nickelates films. The magnon bandwidth of PrNiO2 shows only marginal response to strain-tuning, in sharp contrast to the enhancement of the superconducting transition temperature Tc in the doped superconducting samples. These results suggest the bandwidth of spin excitations of the parent compounds is similar under strain while Tc in the doped ones is not, and thus provide important empirics for the understanding of superconductivity in infinite-layer nickelates.
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Jul 2024
|
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Paul
Worm
,
Qisi
Wang
,
Motoharu
Kitatani
,
Izabela
Bialo
,
Qiang
Gao
,
Xiaolin
Ren
,
Jaewon
Choi
,
Diana
Csontosová
,
Ke-Jin
Zhou
,
Xingjiang
Zhou
,
Zhihai
Zhu
,
Liang
Si
,
Johan
Chang
,
Jan M.
Tomczak
,
Karsten
Held
Diamond Proposal Number(s):
[30189]
Abstract: Infinite-layer nickelates show high-temperature superconductivity, and the experimental phase diagram agrees well with the one simulated within the dynamical vertex approximation (DΓA). Here, we compare the spin-fluctuation spectrum behind these calculations to resonant inelastic x-ray scattering experiments. The overall agreement is good. This independent cross validation of the strength of spin fluctuations strongly supports the scenario, advanced by DΓA, that spin fluctuations are the mediator of the superconductivity observed in nickelates.
|
Jun 2024
|
|
I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Riccardo
Arpaia
,
Leonardo
Martinelli
,
Marco
Moretti Sala
,
Sergio
Caprara
,
Abhishek
Nag
,
Nicholas B.
Brookes
,
Pietro
Camisa
,
Qizhi
Li
,
Qiang
Gao
,
Xingjiang
Zhou
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Enrico
Schierle
,
Thilo
Bauch
,
Ying Ying
Peng
,
Carlo
Di Castro
,
Marco
Grilli
,
Floriana
Lombardi
,
Lucio
Braicovich
,
Giacomo
Ghiringhelli
Diamond Proposal Number(s):
[23880]
Open Access
Abstract: The universality of the strange metal phase in many quantum materials is often attributed to the presence of a quantum critical point (QCP), a zero-temperature phase transition ruled by quantum fluctuations. In cuprates, where superconductivity hinders direct QCP observation, indirect evidence comes from the identification of fluctuations compatible with the strange metal phase. Here we show that the recently discovered charge density fluctuations (CDF) possess the right properties to be associated to a quantum phase transition. Using resonant x-ray scattering, we studied the CDF in two families of cuprate superconductors across a wide doping range (up to p = 0.22). At p* ≈ 0.19, the putative QCP, the CDF intensity peaks, and the characteristic energy Δ is minimum, marking a wedge-shaped region in the phase diagram indicative of a quantum critical behavior, albeit with anomalies. These findings strengthen the role of charge order in explaining strange metal phenomenology and provide insights into high-temperature superconductivity.
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Nov 2023
|
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I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Yingying
Peng
,
Leonardo
Martinelli
,
Qizhi
Li
,
Matteo
Rossi
,
Matteo
Mitrano
,
Riccardo
Arpaia
,
Marco
Moretti Sala
,
Qiang
Gao
,
Xuefei
Guo
,
Gabriella Maria
De Luca
,
Andrew
Walters
,
Abhishek
Nag
,
Andi
Barbour
,
Genda
Gu
,
Jonathan
Pelliciari
,
Nicholas B.
Brookes
,
Peter
Abbamonte
,
Marco
Salluzzo
,
Xingjiang
Zhou
,
Ke-Jin
Zhou
,
Valentina
Bisogni
,
Lucio
Braicovich
,
Steven
Johnston
,
Giacomo
Ghiringhelli
Diamond Proposal Number(s):
[20012]
Abstract: While electron-phonon coupling (EPC) is crucial for Cooper pairing in conventional superconductors, its role in high-
T
c
superconducting cuprates is debated. Using resonant inelastic x-ray scattering at the oxygen
K
edge, we study the EPC in
Bi
2
Sr
2
Ca
Cu
2
O
8
+
δ
(Bi2212) and
Nd
1
+
x
Ba
2
−
x
Cu
3
O
7
−
δ
(NBCO) at different doping levels ranging from heavily underdoped (
p
=
0.07
) to overdoped (
p
=
0.21
). We analyze the data with a localized Lang-Firsov model that allows for the coherent excitations of two phonon modes. While electronic band dispersion effects are non-negligible, we are able to perform a study of the relative values of EPC matrix elements in these cuprate families. In the case of NBCO, the choice of the excitation energy allows us to disentangle modes related to the CuO chains and the
Cu
O
2
planes. Combining the results from the two families, we find the EPC strength decreases with doping at
q
∥
=
(
−
0.25
,
0
)
r.l.u., but has a nonmonotonic trend as a function of doping at smaller momenta. This behavior is attributed to the screening effect of charge carriers. We also find that the phonon intensity is enhanced in the vicinity of the charge-density-wave excitations while the extracted EPC strength appears to be less sensitive to their proximity. By performing a comparative study of two cuprate families, we are able to identify general trends in the EPC for the cuprates and provide experimental input to theories invoking a synergistic role for this interaction in
d
-wave pairing.
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Mar 2022
|
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I03-Macromolecular Crystallography
|
Xiangxi
Wang
,
Ling
Zhu
,
Minghao
Dang
,
Zhongyu
Hu
,
Qiang
Gao
,
Shuai
Yuan
,
Yao
Sun
,
Bo
Zhang
,
Jingshan
Ren
,
Abhay
Kotecha
,
Thomas S.
Walter
,
Junzhi
Wang
,
Elizabeth
Fry
,
David I.
Stuart
,
Zihe
Rao
Abstract: Hepatitis A virus (HAV) infects ∼1.4 million people annually and, although there is a vaccine, there are no licensed therapeutic drugs. HAV is unusually stable (making disinfection problematic) and little is known of how it enters cells and releases its RNA. Here we report a potent HAV-specific monoclonal antibody, R10, which neutralizes HAV infection by blocking attachment to the host cell. High-resolution cryo-EM structures of HAV full and empty particles and of the complex of HAV with R10 Fab reveal the atomic details of antibody binding and point to a receptor recognition site at the pentamer interface. These results, together with our observation that the R10 Fab destabilizes the capsid, suggest the use of a receptor mimic mechanism to neutralize virus infection, providing new opportunities for therapeutic intervention.
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Jan 2017
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I03-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Jingshan
Ren
,
Xiangxi
Wang
,
Ling
Zhu
,
Zhongyu
Hu
,
Qiang
Gao
,
Pan
Yang
,
Xuemei
Li
,
Junzhi
Wang
,
Xinliang
Shen
,
Elizabeth
Fry
,
Zihe
Rao
,
Dave
Stuart
,
K.
Kirkegaard
Diamond Proposal Number(s):
[10627]
Open Access
Abstract: Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) are the primary causes of the epidemics of hand-foot-and-mouth disease (HFMD) that affect more than a million children in China each year and lead to hundreds of deaths. Although there has been progress with vaccines for EV71, the development of a CVA16 vaccine has proved more challenging, and the EV71 vaccine does not give useful cross-protection, despite the capsid proteins of the two viruses sharing about 80% sequence identity. The struc- tural details of the expanded forms of the capsids, which possess nonnative antigenicity, are now well understood, but high resolution information for the native antigenic form of CVA16 has been missing. Here, we remedy this with high resolution X-ray structures of both mature and natural empty CVA16 particles and also of empty recombinant viruslike particles of CVA16 produced in insect cells, a potential vaccine antigen. All three structures are unexpanded native particles and antigenically identical. The recombinant particles have recruited a lipid moiety to stabilize the native antigenic state that is different from the one used in a natural virus infection. As expected, the mature CVA16 virus is similar to EV71; however, structural and immunogenic com- parisons highlight differences that may have implications for vaccine production.
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Sep 2015
|
|
I03-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Xiangxi
Wang
,
Jingshan
Ren
,
Qiang
Gao
,
Zhongyu
Hu
,
Yao
Sun
,
Xuemei
Li
,
David J.
Rowlands
,
Weidong
Yin
,
Junzhi
Wang
,
David I.
Stuart
,
Zihe
Rao
,
Elizabeth E.
Fry
Abstract: Hepatitis A virus (HAV) remains enigmatic, despite 1.4 million cases worldwide annually. It differs radically from other picornaviruses, existing in an enveloped form and being unusually stable, both genetically and physically, but has proved difficult to study. Here we report high-resolution X-ray structures for the mature virus and the empty particle. The structures of the two particles are indistinguishable, apart from some disorder on the inside of the empty particle. The full virus contains the small viral protein VP4, whereas the empty particle harbours only the uncleaved precursor, VP0. The smooth particle surface is devoid of depressions that might correspond to receptor-binding sites. Peptide scanning data extend the previously reported VP3 antigenic site, while structure-based predictions suggest further epitopes. HAV contains no pocket factor and can withstand remarkably high temperature and low pH, and empty particles are even more robust than full particles. The virus probably uncoats via a novel mechanism, being assembled differently to other picornaviruses. It utilizes a VP2 'domain swap' characteristic of insect picorna-like viruses and structure-based phylogenetic analysis places HAV between typical picornaviruses and the insect viruses. The enigmatic properties of HAV may reflect its position as a link between ‘modern’ picornaviruses and the more ‘primitive’ precursor insect viruses; for instance, HAV retains the ability to move from cell-to-cell by transcytosis.
|
Oct 2014
|
|
I03-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Jingshan
Ren
,
Xiangxi
Wang
,
Zhongyu
Hu
,
Qiang
Gao
,
Yao
Sun
,
Xuemei
Li
,
Claudine
Porta
,
Thomas
Walter
,
Robert
Gilbert
,
Yuguang
Zhao
,
Danny
Axford
,
Mark
Williams
,
Katherine
Mcauley
,
David J.
Rowlands
,
Weidong
Yin
,
Junzhi
Wang
,
David I.
Stuart
,
Zihe
Rao
,
Elizabeth E.
Fry
Open Access
Abstract: It remains largely mysterious how the genomes of non-enveloped eukaryotic viruses are transferred across a membrane into the host cell. Picornaviruses are simple models for such viruses, and initiate this uncoating process through particle expansion, which reveals channels through which internal capsid proteins and the viral genome presumably exit the particle, although this has not been clearly seen until now. Here we present the atomic structure of an uncoating intermediate for the major human picornavirus pathogen CAV16, which reveals VP1 partly extruded from the capsid, poised to embed in the host membrane. Together with previous low-resolution results, we are able to propose a detailed hypothesis for the ordered egress of the internal proteins, using two distinct sets of channels through the capsid, and suggest a structural link to the condensed RNA within the particle, which may be involved in triggering RNA release.
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Jun 2013
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