THEORY OF CRITICAL CHARGE FLUCTUATIONS AND PSEUDOGAP FORMATION IN THE SINGLE-BAND HUBBARD MODEL

Within a single-band Hubbard model, treated by means of a strong-coupling approach based on a cumulant expansion, we investigate the existence of critical charge fluctuations (CCF) that could give rise to a phase separation (PS) or a charge density wave, by means of a Bethe-Salpeter equation for the vertex function in the particle-hole channel. We discuss the relevance of the precursor effects of charge ordering on the self-energy of the electrons and the non-Fermi liquid behavior arising from an effective electron-electron interaction.

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Ultrafast manipulation of mirror domain walls in a charge density wave

Science Advances ◽

10.1126/sciadv.aau5501 ◽

2018 ◽

Vol 4 (10) ◽

pp. eaau5501 ◽

Cited By ~ 16

Author(s):

Alfred Zong ◽

Xiaozhe Shen ◽

Anshul Kogar ◽

Linda Ye ◽

Carolyn Marks ◽

...

Keyword(s):

Charge Density ◽

Charge Density Wave ◽

Room Temperature ◽

Domain Walls ◽

Density Wave ◽

Charge Ordering ◽

Time Resolved ◽

Insulator Metal Transition ◽

Femtosecond Light Pulse ◽

A Charge

Domain walls (DWs) are singularities in an ordered medium that often host exotic phenomena such as charge ordering, insulator-metal transition, or superconductivity. The ability to locally write and erase DWs is highly desirable, as it allows one to design material functionality by patterning DWs in specific configurations. We demonstrate such capability at room temperature in a charge density wave (CDW), a macroscopic condensate of electrons and phonons, in ultrathin 1T-TaS2. A single femtosecond light pulse is shown to locally inject or remove mirror DWs in the CDW condensate, with probabilities tunable by pulse energy and temperature. Using time-resolved electron diffraction, we are able to simultaneously track anti-synchronized CDW amplitude oscillations from both the lattice and the condensate, where photoinjected DWs lead to a red-shifted frequency. Our demonstration of reversible DW manipulation may pave new ways for engineering correlated material systems with light.

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X-ray diffraction single-crystal structure characterization of iron ludwigite from room temperature to 15 K

Journal of Applied Crystallography ◽

10.1107/s0021889805036344 ◽

2006 ◽

Vol 39 (1) ◽

pp. 42-45 ◽

Cited By ~ 28

Author(s):

M. Mir ◽

Jan Janczak ◽

Y. P. Mascarenhas

Keyword(s):

Single Crystal ◽

Room Temperature ◽

Structural Characteristics ◽

Density Wave ◽

Charge Ordering ◽

Structure Characterization ◽

Dimensional Structure ◽

X Ray ◽

Extra Electron ◽

A Charge

Iron ludwigite exhibits a superstructure between 283 and 144 K. Anomalies in its transport properties are due to a structural transition related to a charge-ordering phenomenon in the low-dimensional structure. This ordering produces a commensurate transversal charge density wave in the system. To understand these structural characteristics, an X-ray single-crystal diffraction study has been performed at 300 and 15 K. No changes were found in the crystalline structure, except for contraction of the cell volume. The bond-valence sum for each cation shows that at room temperature each Fe4—Fe2—Fe4 triad is composed of three Fe3+ions with one extra electron per triad, and at 15 K in each Fe4a—Fe2—Fe4btriad the extra electron is accommodated in the Fe4a—Fe2 pair of each triad.

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Hidden Charge Orders in Low-Dimensional Mott Insulators

Applied Sciences ◽

10.3390/app9040784 ◽

2019 ◽

Vol 9 (4) ◽

pp. 784

Author(s):

Serena Fazzini ◽

Arianna Montorsi

Keyword(s):

Hubbard Model ◽

Density Wave ◽

Finite Size ◽

Charge Order ◽

Mott Insulators ◽

Coulomb Interactions ◽

Non Local ◽

Low Dimensional ◽

A Charge ◽

Insulating Phase

The opening of a charge gap driven by interaction is a fingerprint of the transition to a Mott insulating phase. In strongly correlated low-dimensional quantum systems, it can be associated to the ordering of hidden non-local operators. For Fermionic 1D models, in the presence of spin–charge separation and short-ranged interaction, a bosonization analysis proves that such operators are the parity and/or string charge operators. In fact, a finite fractional non-local parity charge order is also capable of characterizing some two-dimensional Mott insulators, in both the Fermionic and the bosonic cases. When string charge order takes place in 1D, degenerate edge modes with fractional charge appear, peculiar of a topological insulator. In this article, we review the above framework, and we test it to investigate through density-matrix-renormalization-group (DMRG) numerical analysis the robustness of both hidden orders at half-filling in the 1D Fermionic Hubbard model extended with long range density-density interaction. The preliminary results obtained at finite size including several neighbors in the case of dipolar, screened and unscreened repulsive Coulomb interactions, confirm the phase diagram of the standard extended Hubbard model. Besides the trivial Mott phase, the bond ordered and charge density wave insulating phases are also not destroyed by longer ranged interaction, and still manifest hidden non-local orders.

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The effective electron-electron interaction in the 2D Hubbard model

Journal of Physics and Chemistry of Solids ◽

10.1016/0022-3697(93)90151-g ◽

1993 ◽

Vol 54 (10) ◽

pp. 1109-1113 ◽

Cited By ~ 6

Author(s):

N. Bulut ◽

D.J. Scalapino

Keyword(s):

Hubbard Model ◽

Electron Interaction ◽

Effective Electron

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IMPURITIES IN A MAGNETIC-FIELD-INDUCED LUTTINGER LIQUID

International Journal of Modern Physics B ◽

10.1142/s0217979202013377 ◽

2002 ◽

Vol 16 (20n22) ◽

pp. 2981-2984

Author(s):

S.-W. TSAI ◽

D. L. MASLOV ◽

L. I. GLAZMAN

Keyword(s):

Magnetic Field ◽

Cross Section ◽

Density Wave ◽

Luttinger Liquid ◽

Scaling Behavior ◽

Electron Interaction ◽

Temperature Dependent ◽

Interacting Electrons ◽

A Charge ◽

Quantizing Magnetic Field

We study the effect of dilute impurities on a system of interacting electrons subject to a quantizing magnetic field. For the case of point impurities, the calculation of the scattering cross section can be mapped onto a 1D problem of tunnelinng conductance through a barrier for interacting electrons. We find that the electron-electron interaction produces temperature-dependent corrections to the cross-section, and thus to the tensor of conductivities. Upon summation of the most diverging corrections in all orders of perturbation theory, a scaling behavior of the conductivities emerges. This behavior is similar to that of 1D Luttinger liquid. The scaling exponents depend on the magnetic field and are calculated explicitly in the weak-coupling limit. The limitations on the scaling behavior due to the formation of a charge-density wave are also discussed.

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