scholarly journals Unconventional superconductivity in magic-angle graphene superlattices

Nature ◽  
2018 ◽  
Vol 556 (7699) ◽  
pp. 43-50 ◽  
Author(s):  
Yuan Cao ◽  
Valla Fatemi ◽  
Shiang Fang ◽  
Kenji Watanabe ◽  
Takashi Taniguchi ◽  
...  
Nanoscale ◽  
2021 ◽  
Author(s):  
Liangbing Ge ◽  
Ni Kun ◽  
Xiaojun Wu ◽  
Zhengping Fu ◽  
Yalin Lu ◽  
...  

Recent experiments on magic-angle twisted bi-layer graphene have attracted an intensive attention due to exotic properties such as unconventional superconductivity and correlated insulation. These phenomena were often found at a...


Author(s):  
Wenxiang Liu ◽  
Yongqiang Wu ◽  
Yang Hong ◽  
Bo Hou ◽  
Jingchao Zhang ◽  
...  

It was recently reported that a magic angle, i.e. 1.1º, exists in twisted bilayer graphene which could lead to intrinsic unconventional superconductivity. Variations of the twisting angle between different graphene...


Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.


2001 ◽  
Vol 4 (4) ◽  
pp. 333-351 ◽  
Author(s):  
G. Lippens ◽  
R. Warrass ◽  
J. Wieruszeski ◽  
P. Rousselot-Pailley ◽  
G. Chessari

1994 ◽  
Vol 49 (1-2) ◽  
pp. 19-26 ◽  
Author(s):  
B. Blümich

Abstract Recent developments, focussing on reduction of the rf excitation power by stochastic excitation, on improvements in sensitivity and excitation bandwidth by magic angle spinning, and on combining wideline spectroscopy with spatial resolution for investigations o f spatially inhomogeneous objects are reviewed.


2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii410-iii410
Author(s):  
Christopher Bennett ◽  
Sarah Kohe ◽  
Florence Burte ◽  
Heather Rose ◽  
Debbie Hicks ◽  
...  

Abstract SHH medulloblastoma patients have a variable prognosis. Infants (&lt;3–5 years at diagnosis) are associated with a good prognosis, while disease-course in childhood is associated with specific prognostic biomarkers (MYCN amplification, TP53 mutation, LCA histology; all high-risk). There is an unmet need to identify prognostic subgroups of SHH tumours rapidly in the clinical setting, to aid in real-time risk stratification and disease management. Metabolite profiling is a powerful technique for characterising tumours. High resolution magic angle spinning NMR spectroscopy (HR-MAS) can be performed on frozen tissue samples and provides high quality metabolite information. We therefore assessed whether metabolite profiles could identify subsets of SHH tumours with prognostic potential. Metabolite concentrations of 22 SHH tumours were acquired by HR-MAS and analysed using unsupervised hierarchical clustering. Methylation profiling assigned the infant and childhood SHH subtypes, and clinical and molecular features were compared between clusters. Two clusters were observed. A significantly higher concentration of lipids was observed in Cluster 1 (t-test, p=0.012). Cluster 1 consisted entirely of childhood-SHH whilst Cluster 2 included both childhood-SHH and infant-SHH subtypes. Cluster 1 was enriched for high-risk markers - LCA histology (3/7 v. 0/5), MYCN amplification (2/7 v. 0/5), TP53 mutations (3/7 v. 1/5) and metastatic disease - whilst having a lower proportion of TERT mutations (0/7 v. 2/5) than Cluster 2. These pilot results suggest that (i) it is possible to identify childhood-SHH patients linked to high-risk clinical and molecular biomarkers using metabolite profiles and (ii) these may be detected non-invasively in vivo using magnetic-resonance spectroscopy.


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