scholarly journals Quantum billiards with correlated electrons confined in triangular transition metal dichalcogenide monolayer nanostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jan Ravnik ◽  
Yevhenii Vaskivskyi ◽  
Jaka Vodeb ◽  
Polona Aupič ◽  
Igor Vaskivskyi ◽  
...  
Keyword(s):  
Transition Metal ◽  
Quantum Interference ◽  
Equilibrium Phase ◽  
Atomic Scale ◽  
Localized States ◽  
Correlated Electrons ◽  
Transition Metal Dichalcogenide ◽  
Strongly Correlated Electron ◽  
Correlated Electron ◽  
Unit Cells

AbstractForcing systems through fast non-equilibrium phase transitions offers the opportunity to study new states of quantum matter that self-assemble in their wake. Here we study the quantum interference effects of correlated electrons confined in monolayer quantum nanostructures, created by femtosecond laser-induced quench through a first-order polytype structural transition in a layered transition-metal dichalcogenide material. Scanning tunnelling microscopy of the electrons confined within equilateral triangles, whose dimensions are a few crystal unit cells on the side, reveals that the trajectories are strongly modified from free-electron states both by electronic correlations and confinement. Comparison of experiments with theoretical predictions of strongly correlated electron behaviour reveals that the confining geometry destabilizes the Wigner/Mott crystal ground state, resulting in mixed itinerant and correlation-localized states intertwined on a length scale of 1 nm. The work opens the path toward understanding the quantum transport of electrons confined in atomic-scale monolayer structures based on correlated-electron-materials.

scholarly journals Indication of Strongly Correlated Electron Transport and Mott Insulator in Disordered Multilayer Ferritin Structures (DMFS)

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4527
Author(s):  
Christopher Rourk ◽  
Yunbo Huang ◽  
Minjing Chen ◽  
Cai Shen
Keyword(s):  
Quantum Dots ◽  
Electron Transport ◽  
Transition Metal ◽  
Strongly Correlated Electrons ◽  
Mott Insulator ◽  
Material Behavior ◽  
Correlated Electrons ◽  
Strongly Correlated ◽  
Strongly Correlated Electron ◽  
Correlated Electron

Electron tunneling in ferritin and between ferritin cores (a transition metal (iron) oxide storage protein) in disordered arrays has been extensively documented, but the electrical behavior of those structures in circuits with more than two electrodes has not been studied. Tests of devices using a layer-by-layer deposition process for forming multilayer arrays of ferritin that have been previously reported indicate that strongly correlated electron transport is occurring, consistent with models of electron transport in quantum dots. Strongly correlated electrons–electrons that engage in strong electron-electron interactions have been observed in transition metal oxides and quantum dots and can create unusual material behavior that is difficult to model, such as switching between a low resistance metal state and a high resistance Mott insulator state. This paper reports the results of the effect of various degrees of structural homogeneity on the electrical characteristics of these ferritin arrays. These results demonstrate for the first time that these structures can provide a switching function associated with the circuit that they are contained within, consistent with the observed behavior of strongly correlated electrons and Mott insulators.

Characterization of Graphene and Transition Metal Dichalcogenide at the Atomic Scale

2015 ◽  
Vol 84 (12) ◽  
pp. 121005 ◽  
Author(s):  
Zheng Liu ◽  
Yung-Chang Lin ◽  
Jamie H. Warner ◽  
Po-Yuan Teng ◽  
Chao-Hui Yeh ◽  
...  
Keyword(s):  
Transition Metal ◽  
Atomic Scale ◽  
Transition Metal Dichalcogenide

NOVEL MANY-BODY EFFECTS IN PHOTOEMISSION AND INVERSE PHOTOEMISSION SPECTRA OF ULTRATHIN TRANSITION-METAL FILMS

1991 ◽  
Vol 05 (08) ◽  
pp. 1147-1178 ◽  
Author(s):  
CHANGFENG CHEN
Keyword(s):  
Transition Metal ◽  
Local Density ◽  
Many Body ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Nickel Iron ◽  
Correlated Electron ◽  
Inverse Photoemission ◽  
Recent Developments ◽  
Many Body Effects

We present an overview of some recent developments in the theoretical modeling of transition-metal systems, particularly the ultrathin-film structures, focusing on the effects of electron-electron interactions. We describe the progress in the understanding of how to model realistic strongly correlated electron systems using and going beyond the local-density-approximation single-particle electronic structures. Results of exact many-body calculations of photoemission and inverse photoemission spectra of ultrathin nickel, iron and cobalt films are shown to illustrate the application of our approach. Interesting new features induced by many-body effects are found and discussed. Comparison with available experimental results is presented and further work, both experimental and theoretical, is suggested.

Quantum interference effect in few-layered transition metal dichalcogenide

2020 ◽  
Vol 20 (3) ◽  
pp. 451-455
Author(s):  
Jinwan Park ◽  
Kenji Yoshida ◽  
Sung Jin An ◽  
Kazuhiko Hirakawa ◽  
Minkyung Jung ◽  
...  
Keyword(s):  
Transition Metal ◽  
Interference Effect ◽  
Quantum Interference ◽  
Transition Metal Dichalcogenide ◽  
Quantum Interference Effect ◽  
Layered Transition Metal

scholarly journals Universal size-dependent nonlinear charge transport in single crystals of the Mott insulator Ca2RuO4

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
G. Avallone ◽  
R. Fermin ◽  
K. Lahabi ◽  
V. Granata ◽  
R. Fittipaldi ◽  
...  
Keyword(s):  
Sample Size ◽  
Single Crystals ◽  
Current Density ◽  
Equilibrium Phase ◽  
Mott Insulator ◽  
Metallic Phase ◽  
Tuning Parameter ◽  
Strongly Correlated Electron ◽  
Simultaneous Application ◽  
Correlated Electron

AbstractThe surprisingly low current density required for inducing the insulator to metal transition has made Ca2RuO4 an attractive candidate material for developing Mott-based electronics devices. The mechanism driving the resistive switching, however, remains a controversial topic in the field of strongly correlated electron systems. Here we probe an uncovered region of phase space by studying high-purity Ca2RuO4 single crystals, using the sample size as principal tuning parameter. Upon reducing the crystal size, we find a four orders of magnitude increase in the current density required for driving Ca2RuO4 out of the insulating state into a non-equilibrium phase which is the precursor to the fully metallic phase. By integrating a microscopic platinum thermometer and performing thermal simulations, we gain insight into the local temperature during simultaneous application of current and establish that the size dependence is not a result of Joule heating. The findings suggest an inhomogeneous current distribution in the nominally homogeneous crystal. Our study calls for a reexamination of the interplay between sample size, charge current, and temperature in driving Ca2RuO4 towards the Mott insulator to metal transition.

scholarly journals Magic in twisted transition metal dichalcogenide bilayers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Trithep Devakul ◽  
Valentin Crépel ◽  
Yang Zhang ◽  
Liang Fu
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Anomalous Hall Effect ◽  
Quantum Spin ◽  
Flat Band ◽  
Magic Angle ◽  
Transition Metal Dichalcogenide ◽  
Strongly Correlated Electron ◽  
Hartree Fock ◽  
The Rich

AbstractThe long-wavelength moiré superlattices in twisted 2D structures have emerged as a highly tunable platform for strongly correlated electron physics. We study the moiré bands in twisted transition metal dichalcogenide homobilayers, focusing on WSe2, at small twist angles using a combination of first principles density functional theory, continuum modeling, and Hartree-Fock approximation. We reveal the rich physics at small twist angles θ < 4∘, and identify a particular magic angle at which the top valence moiré band achieves almost perfect flatness. In the vicinity of this magic angle, we predict the realization of a generalized Kane-Mele model with a topological flat band, interaction-driven Haldane insulator, and Mott insulators at the filling of one hole per moiré unit cell. The combination of flat dispersion and uniformity of Berry curvature near the magic angle holds promise for realizing fractional quantum anomalous Hall effect at fractional filling. We also identify twist angles favorable for quantum spin Hall insulators and interaction-induced quantum anomalous Hall insulators at other integer fillings.

scholarly journals Indication of Highly Correlated Electron Transport and Mott Insulator in Disordered Multilayer Ferritin Structures (DMFS)

2021 ◽  
Author(s):  
Chris Rourk ◽  
Yunbo Huang ◽  
Minjing Chen ◽  
Cai Shen
Keyword(s):  
Quantum Dots ◽  
Electron Transport ◽  
Transition Metal ◽  
Mott Insulator ◽  
Material Behavior ◽  
Switching Function ◽  
Correlated Electrons ◽  
Layer By Layer ◽  
Correlated Electron ◽  
Highly Correlated

Highly-correlated electrons &ndash; electrons that engage in strong electron-electron interactions &ndash; have been observed in transition metal oxides and quantum dots and can create unusual material behavior that is difficult to model, such as switching between a low resistance metal state and a high resistance Mott insulator state. Tests of devices using a layer-by-layer deposition process for forming multilayer arrays of ferritin (a transition metal (iron) oxide storage protein) have been previously reported that indicate that highly-correlated electron transport is occurring, consistent with models of electron transport in quantum dots. This paper reports the results of the effect of various degrees of structural homogeneity on the electrical characteristics of these ferritin arrays, as well as demonstrating that these structures can provide a switching function associated with the circuit that they are contained within, consistent with the observed behavior of highly-correlated electrons.

scholarly journals Kinetic approach to superconductivity hidden behind a competing order

2018 ◽  
Vol 4 (10) ◽  
pp. eaau3489 ◽  
Author(s):  
Hiroshi Oike ◽  
Manabu Kamitani ◽  
Yoshinori Tokura ◽  
Fumitaka Kagawa
Keyword(s):  
Electric Pulse ◽  
Stable State ◽  
Thermal Quenching ◽  
Charge Order ◽  
Kinetic Approach ◽  
Transition Metal Dichalcogenide ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Competing Order

Exploration for superconductivity is one of the research frontiers in condensed matter physics. In strongly correlated electron systems, the emergence of superconductivity is often inhibited by the formation of a thermodynamically more stable magnetic/charge order. Thus, to develop the superconductivity as the thermodynamically most stable state, the free-energy balance between the superconductivity and the competing order has been controlled mainly by changing thermodynamic parameters, such as the physical/chemical pressure and carrier density. However, such a thermodynamic approach may not be the only way to materialize the superconductivity. We present a new kinetic approach to avoiding the competing order and thereby inducing persistent superconductivity. In the transition-metal dichalcogenide IrTe2as an example, by using current pulse–based rapid cooling of up to ~107K s−1, we successfully kinetically avoid a first-order phase transition to a competing charge order and uncover metastable superconductivity hidden behind. Because the electronic states at low temperatures depend on the history of thermal quenching, electric pulse applications enable nonvolatile and reversible switching of the metastable superconductivity, a unique advantage of the kinetic approach. Thus, our findings provide a new approach to developing and manipulating superconductivity beyond the framework of thermodynamics.

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