scholarly journals Observation of Correlated Particle-Hole Pairs and String Order in Low-Dimensional Mott Insulators

Science ◽  
2011 ◽  
Vol 334 (6053) ◽  
pp. 200-203 ◽  
Author(s):  
M. Endres ◽  
M. Cheneau ◽  
T. Fukuhara ◽  
C. Weitenberg ◽  
P. Schauss ◽  
...  
Keyword(s):  
Mott Insulators ◽  
Low Dimensional

scholarly journals Hidden Charge Orders in Low-Dimensional Mott Insulators

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.

scholarly journals Spin gap in low-dimensional Mott insulators with orbital degeneracy

1999 ◽  
Vol 85 (8) ◽  
pp. 5327-5329 ◽  
Author(s):  
L. Guidoni ◽  
G. Santoro ◽  
S. Sorella ◽  
A. Parola ◽  
E. Tosatti
Keyword(s):  
Mott Insulators ◽  
Spin Gap ◽  
Orbital Degeneracy ◽  
Low Dimensional

Thermoelectric Properties of PbSr(Se,Te)-Based Low Dimensional Structures

2000 ◽  
Vol 626 ◽  
Author(s):  
Harald Beyer ◽  
Joachim Nurnus ◽  
Harald Böttner ◽  
Armin Lambrecht ◽  
Lothar Schmitt ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Evaluation Method ◽  
Interband Transition ◽  
Multiple Quantum Well ◽  
Calculated Data ◽  
Multiple Quantum ◽  
Ir Transmission ◽  
Low Dimensional

ABSTRACTThermoelectric properties of low dimensional structures based on PbTe/PbSrTe-multiple quantum-well (MQW)-structures with regard to the structural dimensions, doping profiles and levels are presented. Interband transition energies and barrier band-gap are determined from IR-transmission spectra and compared with Kronig-Penney calculations. The influence of the data evaluation method to obtain the 2D power factor will be discussed. The thermoelectrical data of our layers show a more modest enhancement in the power factor σS2 compared with former publications and are in good agreement with calculated data from Broido et al. [5]. The maximum allowed doping level for modulation doped MQW structures is determined. Thermal conductivity measurements show that a ZT enhancement can be achieved by reducing the thermal conductivity due to interface scattering. Additionally promising lead chalcogenide based superlattices for an increased 3D figure of merit are presented.

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