| 1. |
- Kanai, M, et al.
(författare)
-
- 2023
-
swepub:Mat__t
|
|
| 2. |
- Niemi, MEK, et al.
(författare)
-
- 2021
-
swepub:Mat__t
|
|
| 3. |
- Küspert, Julia, et al.
(författare)
-
Pseudogap suppression by competition with superconductivity in La-based cuprates
- 2022
-
Ingår i: Physical Review Research. - 2643-1564. ; 4:4
-
Tidskriftsartikel (refereegranskat)abstract
- We carried out a comprehensive high-resolution angle-resolved photoemission spectroscopy (ARPES) study of the pseudogap interplay with superconductivity in La-based cuprates. The three systems La2-xSrxCuO4, La1.6-xNd0.4SrxCuO4, and La1.8-xEu0.2SrxCuO4 display slightly different pseudogap critical points in the temperature versus doping phase diagram. We studied the pseudogap evolution into the superconducting state for doping concentrations just below the critical point. In this setting, near optimal doping for superconductivity and in the presence of the weakest possible pseudogap, we uncover how the pseudogap is partially suppressed inside the superconducting state. This conclusion is based on the direct observation of a reduced pseudogap energy scale and re-emergence of spectral weight suppressed by the pseudogap. Altogether these observations suggest that the pseudogap phenomenon in La-based cuprates is in competition with superconductivity for antinodal spectral weight.
|
|
| 4. |
- Sutter, D., et al.
(författare)
-
Hallmarks of Hunds coupling in the Mott insulator Ca2RuO4
- 2017
-
Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- A paradigmatic case of multi-band Mott physics including spin-orbit and Hund's coupling is realized in Ca2RuO4. Progress in understanding the nature of this Mott insulating phase has been impeded by the lack of knowledge about the low-energy electronic structure. Here we provide-using angle-resolved photoemission electron spectroscopy-the band structure of the paramagnetic insulating phase of Ca2RuO4 and show how it features several distinct energy scales. Comparison to a simple analysis of atomic multiplets provides a quantitative estimate of the Hund's coupling J = 0.4 eV. Furthermore, the experimental spectra are in good agreement with electronic structure calculations performed with Dynamical Mean-Field Theory. The crystal field stabilization of the d(xy) orbital due to c-axis contraction is shown to be essential to explain the insulating phase. These results underscore the importance of multi-band physics, Coulomb interaction and Hund's coupling that together generate the Mott insulating state of Ca2RuO4.
|
|
| 5. |
|
|
| 6. |
- Matt, C. E., et al.
(författare)
-
Electron scattering, charge order, and pseudogap physics in La1.6-xNd0.4SrxCuO4 : An angle-resolved photoemission spectroscopy study
- 2015
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 92:13
-
Tidskriftsartikel (refereegranskat)abstract
- We report an angle-resolved photoemission study of the charge stripe ordered La1.6-xNd0.4SrxCuO4 (Nd-LSCO) system. A comparative and quantitative line-shape analysis is presented as the system evolves from the overdoped regime into the charge ordered phase. On the overdoped side (x = 0.20), a normal-state antinodal spectral gap opens upon cooling below 80 K. In this process, spectral weight is preserved but redistributed to larger energies. A correlation between this spectral gap and electron scattering is found. A different line shape is observed in the antinodal region of charge ordered Nd-LSCO x = 1/8. Significant low-energy spectral weight appears to be lost. These observations are discussed in terms of spectral-weight redistribution and gapping originating from charge stripe ordering.
|
|
| 7. |
- Namkoong, H, et al.
(författare)
-
DOCK2 is involved in the host genetics and biology of severe COVID-19
- 2022
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 609:7928, s. 754-
-
Tidskriftsartikel (refereegranskat)abstract
- Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge1–5. Here we conducted a genome-wide association study (GWAS) involving 2,393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3,289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target.
|
|
| 8. |
- Wang, QBS, et al.
(författare)
-
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
- 2022
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1, s. 4830-
-
Tidskriftsartikel (refereegranskat)abstract
- Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection.
|
|
| 9. |
- Horio, M., et al.
(författare)
-
Electronic reconstruction forming a C-2-symmetric Dirac semimetal in Ca3Ru2O7
- 2021
-
Ingår i: npj Quantum Materials. - : Springer Science and Business Media LLC. - 2397-4648. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Electronic band structures in solids stem from a periodic potential reflecting the structure of either the crystal lattice or electronic order. In the stoichiometric ruthenate Ca3Ru2O7, numerous Fermi surface-sensitive probes indicate a low-temperature electronic reconstruction. Yet, the causality and the reconstructed band structure remain unsolved. Here, we show by angle-resolved photoemission spectroscopy, how in Ca3Ru2O7 a C-2-symmetric massive Dirac semimetal is realized through a Brillouin-zone preserving electronic reconstruction. This Dirac semimetal emerges in a two-stage transition upon cooling. The Dirac point and band velocities are consistent with constraints set by quantum oscillation, thermodynamic, and transport experiments, suggesting that the complete Fermi surface is resolved. The reconstructed structure-incompatible with translational-symmetry-breaking density waves-serves as an important test for band structure calculations of correlated electron systems.
|
|
| 10. |
- Horio, M., et al.
(författare)
-
Orbital-selective metal skin induced by alkali-metal-dosing Mott-insulating Ca 2 RuO 4
- 2023
-
Ingår i: Communications Physics. - 2399-3650. ; 6:1
-
Tidskriftsartikel (refereegranskat)abstract
- Doped Mott insulators are the starting point for interesting physics such as high temperature superconductivity and quantum spin liquids. For multi-band Mott insulators, orbital selective ground states have been envisioned. However, orbital selective metals and Mott insulators have been difficult to realize experimentally. Here we demonstrate by photoemission spectroscopy how Ca2RuO4, upon alkali-metal surface doping, develops a single-band metal skin. Our dynamical mean field theory calculations reveal that homogeneous electron doping of Ca2RuO4 results in a multi-band metal. All together, our results provide evidence for an orbital-selective Mott insulator breakdown, which is unachievable via simple electron doping. Supported by a cluster model and cluster perturbation theory calculations, we demonstrate a type of skin metal-insulator transition induced by surface dopants that orbital-selectively hybridize with the bulk Mott state and in turn produce coherent in-gap states.
|
|
