scholarly journals Probing spin correlations using angle-resolved photoemission in a coupled metallic/Mott insulator system

2020 ◽  
Vol 6 (6) ◽  
pp. eaaz0611 ◽  
Author(s):  
V. Sunko ◽  
F. Mazzola ◽  
S. Kitamura ◽  
S. Khim ◽  
P. Kushwaha ◽  
...  
Keyword(s):  
A Priori ◽  
Model System ◽  
Spin Susceptibility ◽  
Kondo Lattice ◽  
Photoemission Spectroscopy ◽  
Magnetic Oxide ◽  
Spin Correlations ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Charge Spectrum

A nearly free electron metal and a Mott insulating state can be thought of as opposite ends of the spectrum of possibilities for the motion of electrons in a solid. Understanding their interaction lies at the heart of the correlated electron problem. In the magnetic oxide metal PdCrO2, nearly free and Mott-localized electrons exist in alternating layers, forming natural heterostructures. Using angle-resolved photoemission spectroscopy, quantitatively supported by a strong coupling analysis, we show that the coupling between these layers leads to an “intertwined” excitation that is a convolution of the charge spectrum of the metallic layer and the spin susceptibility of the Mott layer. Our findings establish PdCrO2 as a model system in which to probe Kondo lattice physics and also open new routes to use the a priori nonmagnetic probe of photoemission to gain insights into the spin susceptibility of correlated electron materials.

scholarly journals Direct visualization of coexisting channels of interaction in CeSb

2019 ◽  
Vol 5 (3) ◽  
pp. eaat7158 ◽  
Author(s):  
Sooyoung Jang ◽  
Robert Kealhofer ◽  
Caolan John ◽  
Spencer Doyle ◽  
Ji-Sook Hong ◽  
...  
Keyword(s):  
Heavy Fermion ◽  
Real Space ◽  
Photoemission Spectroscopy ◽  
Itinerant Electron ◽  
Electron Systems ◽  
Direct Visualization ◽  
Correlated Electron Systems ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Correlated Electron ◽  
Modes Of Interaction

Our understanding of correlated electron systems is vexed by the complexity of their interactions. Heavy fermion compounds are archetypal examples of this physics, leading to exotic properties that weave magnetism, superconductivity and strange metal behavior together. The Kondo semimetal CeSb is an unusual example where different channels of interaction not only coexist, but have coincident physical signatures, leading to decades of debate about the microscopic picture describing the interactions between the f moments and the itinerant electron sea. Using angle-resolved photoemission spectroscopy, we resonantly enhance the response of the Ce f electrons across the magnetic transitions of CeSb and find there are two distinct modes of interaction that are simultaneously active, but on different kinds of carriers. This study reveals how correlated systems can reconcile the coexistence of different modes on interaction—by separating their action in momentum space, they allow their coexistence in real space.

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.

Recent Advances in Topological Quantum Materials by Angle-Resolved Photoemission Spectroscopy

Matter ◽  
2020 ◽  
Vol 3 (4) ◽  
pp. 1114-1141
Author(s):  
Yujie Chen ◽  
Xu Gu ◽  
Yiwei Li ◽  
Xian Du ◽  
Lexian Yang ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Recent Advances ◽  
Topological Quantum ◽  
Quantum Materials
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