Correlated electron physics in two-level quantum dots: Phase transitions, transport, and experiment

2009 ◽  
Vol 80 (12) ◽  
Author(s):  
David E. Logan ◽  
Christopher J. Wright ◽  
Martin R. Galpin
Keyword(s):  
Quantum Dots ◽  
Phase Transitions ◽  
Correlated Electron

Charge ordering and ferroelectric states in organic quasi-one-dimensional conductors

2002 ◽  
Vol 12 (9) ◽  
pp. 133-138
Author(s):  
F. Nad ◽  
P. Monceau
Keyword(s):  
Phase Transitions ◽  
Charge Ordering ◽  
Electron Interaction ◽  
Charge Symmetry ◽  
Low Frequencies ◽  
One Dimensional ◽  
Thermally Activated ◽  
Correlated Electron ◽  
Temperature Dependences ◽  
New Phase

In quasi-one-dimensional (TMTTF)2X conductors [1], where X are the various centro-symmetrical and non-centrosymmetrical anions, by study of temperature dependences of conductance G and dielectric permittivity $\varepsilon '$ at low frequencies we have found anomalies which are characteristic for phase transitions: an abrupt bend on the G(l/T) dependences with thermally activated decrease of G and sharp maxima of the E' near the charge ordering temperature corresponding to the E' divergence according to the Curie law. A number of evidences have been obtained in favor that driving force of these phase transitions is the long range correlated electron interaction yielding the charge ordering along the molecular chains (a lattice version of the Wigner crystal). The anion chains, electrically balanced with molecular chains, are of very importance in the formation and the stabilization of these new phase states. It appears that the form of charge symmetry of the anions determines to a great extent the types of the occurring transitions and the developing ground states.

scholarly journals Cutoff-independent RG flow equations for two-coupled chains model

2014 ◽  
Vol 28 (32) ◽  
pp. 1450247
Author(s):  
Thiago Prudêncio
Keyword(s):  
Phase Transitions ◽  
Energy Scale ◽  
Strongly Correlated Electron ◽  
Flow Equations ◽  
Correlated Electron ◽  
Independent Form ◽  
Cutoff Dependence ◽  
Dependent Form ◽  
Explicit Consideration ◽  
Spinless Case

One-dimensional strongly correlated electron systems coupled via transverse hopping and presence of interband interactions can converge to a Luttinger liquid state or diverge to an even more intricate behavior, as a Mott state. Explicit consideration of the renormalization group (RG) flow of the Fermi points in the Fermi surface, turns the classification of phase transitions more challenging. We reconsider the recent paper for the spinless case [E. Correa and A. Ferraz, Eur. Phys. J. B 87 (2014) 51], where RG flow equations are derived in a cutoff-dependent form up to two-loops order. We demonstrate that the cutoff-dependence can be removed by rewriting the RG flow equations in terms of the energy scale variable. In our paper, the RG flow equations assume a cutoff-independent form and leads to fixed points independent of cutoff choice. The consequence is the invariance under cutoff transformations, more suitable for classifying universality classes and phase transitions.

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