scholarly journals Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasers

2014 ◽  
Vol 195 ◽  
pp. 231-236 ◽  
Author(s):  
S. Eich ◽  
A. Stange ◽  
A.V. Carr ◽  
J. Urbancic ◽  
T. Popmintchev ◽  
...  
Keyword(s):  
High Harmonic ◽  
Photoemission Spectroscopy ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Ti:Sapphire Lasers

scholarly journals Photoinduced possible superconducting state with long-lived disproportionate band filling in FeSe

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Takeshi Suzuki ◽  
Takashi Someya ◽  
Takahiro Hashimoto ◽  
Shoya Michimae ◽  
Mari Watanabe ◽  
...  
Keyword(s):  
Superconducting State ◽  
Degrees Of Freedom ◽  
Extreme Ultraviolet ◽  
High Harmonic ◽  
Photoemission Spectroscopy ◽  
Iron Based Superconductors ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Dynamical Behaviors ◽  
Band Filling ◽  
Iron Based

Abstract Photoexcitation is a very powerful way to instantaneously drive a material into a novel quantum state without any fabrication, and variable ultrafast techniques have been developed to observe how electron, lattice, and spin degrees of freedom change. One of the most spectacular phenomena is photoinduced superconductivity, and it has been suggested in cuprates that the transition temperature Tc can be enhanced from the original Tc with significant lattice modulations. Here, we show a possibility for another photoinduced high-Tc superconducting state in the iron-based superconductor FeSe. The transient electronic state over the entire Brillouin zone is directly observed by time- and angle-resolved photoemission spectroscopy using extreme ultraviolet pulses obtained from high harmonic generation. Our results of dynamical behaviors from 50 fs to 800 ps consistently support the favourable superconducting state after photoexcitation well above Tc. This finding demonstrates that multiband iron-based superconductors emerge as an alternative candidate for photoinduced superconductors.

scholarly journals Time and angle resolved photoemission spectroscopy using femtosecond visible and high-harmonic light

2009 ◽  
Vol 148 ◽  
pp. 012042 ◽  
Author(s):  
S Mathias ◽  
M Wiesenmayer ◽  
F Deicke ◽  
A Ruffing ◽  
L Miaja-Avila ◽  
...  
Keyword(s):  
High Harmonic ◽  
Photoemission Spectroscopy ◽  
Angle Resolved Photoemission Spectroscopy

scholarly journals Evidence for a large Rashba splitting in PtPb4 from angle-resolved photoemission spectroscopy

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Kyungchan Lee ◽  
Daixiang Mou ◽  
Na Hyun Jo ◽  
Yun Wu ◽  
Benjamin Schrunk ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Angle Resolved Photoemission Spectroscopy

scholarly journals Observation of a singular Weyl point surrounded by charged nodal walls in PtGa

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J.-Z. Ma ◽  
Q.-S. Wu ◽  
M. Song ◽  
S.-N. Zhang ◽  
E. B. Guedes ◽  
...  
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Photoemission Spectroscopy ◽  
Functional Theory ◽  
Fermi Arc ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Fermi Arcs ◽  
Surface Projection ◽  
Applicable Range ◽  
Opposite Chirality

AbstractConstrained by the Nielsen-Ninomiya no-go theorem, in all so-far experimentally determined Weyl semimetals (WSMs) the Weyl points (WPs) always appear in pairs in the momentum space with no exception. As a consequence, Fermi arcs occur on surfaces which connect the projections of the WPs with opposite chiral charges. However, this situation can be circumvented in the case of unpaired WP, without relevant surface Fermi arc connecting its surface projection, appearing singularly, while its Berry curvature field is absorbed by nontrivial charged nodal walls. Here, combining angle-resolved photoemission spectroscopy with density functional theory calculations, we show experimentally that a singular Weyl point emerges in PtGa at the center of the Brillouin zone (BZ), which is surrounded by closed Weyl nodal walls located at the BZ boundaries and there is no Fermi arc connecting its surface projection. Our results reveal that nontrivial band crossings of different dimensionalities can emerge concomitantly in condensed matter, while their coexistence ensures the net topological charge of different dimensional topological objects to be zero. Our observation extends the applicable range of the original Nielsen-Ninomiya no-go theorem which was derived from zero dimensional paired WPs with opposite chirality.

scholarly journals Emergent flat band electronic structure in a VSe2/Bi2Se3 heterostructure

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Turgut Yilmaz ◽  
Xiao Tong ◽  
Zhongwei Dai ◽  
Jerzy T. Sadowski ◽  
Eike F. Schwier ◽  
...  
Keyword(s):  
Dirac Point ◽  
Electronic States ◽  
Quantum States ◽  
Photoemission Spectroscopy ◽  
Flat Band ◽  
Strongly Correlated ◽  
Dirac Cone ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Topological Materials ◽  
Photoemission Study

AbstractFlat band electronic states are proposed to be a fundamental tool to achieve various quantum states of matter at higher temperatures due to the enhanced electronic correlations. However, materials with such peculiar electronic states are rare and often rely on subtle properties of the band structures. Here, by using angle-resolved photoemission spectroscopy, we show the emergent flat band in a VSe2 / Bi2Se3 heterostructure. Our photoemission study demonstrates that the flat band covers the entire Brillouin zone and exhibits 2D nature with a complex circular dichroism. In addition, the Dirac cone of Bi2Se3 is not reshaped by the flat band even though they overlap in proximity of the Dirac point. These features make this flat band distinguishable from the ones previously found. Thereby, the observation of a flat band in the VSe2 / Bi2Se3 heterostructure opens a promising pathway to realize strongly correlated quantum effects in topological materials.

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