scholarly journals From basic properties to the Mott design of correlated delafossites

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Frank Lechermann
Keyword(s):  
Electronic Structure ◽  
Electronic States ◽  
Decisive Role ◽  
Research Field ◽  
Critical Regime ◽  
Flat Band ◽  
Layered Oxides ◽  
Basic Properties ◽  
Interacting Systems ◽  
Experimental Preparation

AbstractThe natural-heterostructure concept realized in delafossites highlights these layered oxides. While metallic, band- or Mott-insulating character may be associated with individual layers, inter-layer coupling still plays a decisive role. We review the correlated electronic structure of PdCoO2, PdCrO2, and AgCrO2, showing that layer-entangled electronic states can deviate from standard classifications of interacting systems. This finding opens up possibilities for materials design in a subtle Mott-critical regime. Manipulated Hidden-Mott physics, correlation-induced semimetallicity, or Dirac/flat-band dispersions in a Mott background are emerging features. Together with achievements in the experimental preparation, this inaugurates an exciting research field in the arena of correlated materials.

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.

SPACE-CHARGE SPECTROSCOPY OF ELECTRONIC STATES IN Ge/Si QUANTUM DOTS WITH TYPE-II BAND ALIGNMENT

2007 ◽  
Vol 06 (05) ◽  
pp. 353-356
Author(s):  
A. I. YAKIMOV ◽  
A. V. DVURECHENSKII ◽  
A. I. NIKIFOROV ◽  
A. A. BLOSHKIN
Keyword(s):  
Quantum Dots ◽  
Electronic Structure ◽  
Binding Energy ◽  
Space Charge ◽  
Tensile Strain ◽  
Electronic States ◽  
Band Alignment ◽  
Type Ii ◽  
Electron Confinement ◽  
Si Quantum Dots

Space-charge spectroscopy was employed to study electronic structure in a stack of four layers of Ge quantum dots coherently embedded in an n-type Si (001) matrix. Evidence for an electron confinement in the vicinity of Ge dots was found. From the frequency-dependent measurements the electron binding energy was determined to be ~50 meV, which is consistent with the results of numerical analysis. The data are explained by a modification of the conduction band alignment induced by inhomogeneous tensile strain in Si around the buried Ge dots.

scholarly journals Theoretical Electronic Structure of the Lowest-Lying Electronic States of the CaBr Molecule

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
H. Jawhari ◽  
M. Korek ◽  
R. Awad ◽  
M. R. Sakr
Keyword(s):  
Electronic Structure ◽  
Electronic States

scholarly journals Роль состояний переноса заряда "лиганд-металл" в процессах возбуждения люминесценции индолкарбоксилатов европия

2022 ◽  
Vol 130 (1) ◽  
pp. 121
Author(s):  
В.И. Царюк ◽  
К.П. Журавлев
Keyword(s):  
Excitation Energy Transfer ◽  
Electronic States ◽  
Decisive Role ◽  
Low Energy ◽  
Excitation Spectra ◽  
Metal Charge ◽  
Ternary Compounds ◽  
Aromatic Carboxylates ◽  
Metal Charge Transfer

The luminescence excitation energy transfer in europium and terbium indole-3-carboxylates, indole-3-acetates and indole-3-propionates as well as ternary indolecarboxylates containing 1,10-phenanthroline and 2,2'-bipyridine molecules have been studied. The luminescence excitation spectra, the lifetimes of the 5D0 (Eu3+) and 5D4 (Tb3+) states, and the luminescence intensity are analyzed. The decisive role of ligand-metal charge transfer (LMCT) states in the quenching of the luminescence of europium aromatic carboxylates containing a π-excessive pyrrole or indole fragment is demonstrated. Most europium compounds are characterized by quenching due to the depopulation of the 5D0 state of the Eu3+ ion through the low-energy LMCT state. But in some ternary compounds, the LMCT state being of higher energy participates in the nonradiative depopulation of the excited electronic states of the ligand.

scholarly journals The Basic Properties of the Electronic Structure of the Oxygen-evolving Complex of Photosystem II Are Not Perturbed by Ca2+Removal

2012 ◽  
Vol 287 (29) ◽  
pp. 24721-24733 ◽  
Author(s):  
Thomas Lohmiller ◽  
Nicholas Cox ◽  
Ji-Hu Su ◽  
Johannes Messinger ◽  
Wolfgang Lubitz
Keyword(s):  
Electronic Structure ◽  
Photosystem Ii ◽  
Oxygen Evolving Complex ◽  
Basic Properties ◽  
Oxygen Evolving

Relation between oxygen stoichiometry and thermodynamic properties and the electronic structure of nonstoichiometric perovskite La0.6Sr0.4CoO3−δ

2016 ◽  
Vol 18 (42) ◽  
pp. 29543-29548 ◽  
Author(s):  
S. F. Bychkov ◽  
A. G. Sokolov ◽  
M. P. Popov ◽  
A. P. Nemudry
Keyword(s):  
Electronic Structure ◽  
Thermodynamic Properties ◽  
Fermi Level ◽  
Electronic States ◽  
Oxygen Activity ◽  
Oxygen Stoichiometry ◽  
Itinerant Electron ◽  
Electron Model ◽  
Density Of Electronic States

Within the framework of the itinerant electron model, the dependence of the oxide nonstoichiometry on the oxygen activity was related to the density of electronic states near the Fermi level.

New Technique for Ohmic Formation

1996 ◽  
Vol 427 ◽  
Author(s):  
S. Hara ◽  
T. Teraji ◽  
H. Okushi ◽  
K. Kajimura
Keyword(s):  
Work Function ◽  
Barrier Height ◽  
Electronic States ◽  
Surface States ◽  
Interface States ◽  
Hot Water ◽  
Flat Band ◽  
Interface Charges ◽  
The Difference ◽  
Density Of Interface States

AbstractWe propose a new systematical method to control Schottky barrier heights of metal/semiconductor interfaces by controlling the density of interface electronic states and the number of charges in the states. The density of interface states is controlled by changing the density of surface electronic states, which is controlled by surface hydrogenation and flattening the surface atomically. We apply establishing hydrogen termination techniques using a chemical solution, pH controlled buffered HF or hot water. Also, slow oxidation by oxygen gas was used to flatten resultant semiconductor surfaces. The density of interface charges is changeable by controlling a metal work function. When the density of surface states is reduced enough to unpin the Fermi level, the barrier height is determined simply by the difference between the work function of a metal φm and the flat-band semiconductor ØsFB. In such an interface with the low density of interface states, an Ohmic contact with a zero barrier height is formed when we select a metal with φm < φsFB. We have already demonstrated controlling Schottky and Ohmic properties by changing the pinning degree on silicon carbide (0001) surfaces. Further, on an atomically-flat Si(111) surface with monohydride termination, we have observed the lowering of an Al barrier height.

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