Charge density glass from fictions to facts

Ultrasonic properties near 50 K of the quasi-one-dimensional conductors A0.30MoO3(A = K, Rb) and Rb0.30(Mo1−xVx)O3

“…Therefore, the onset of the anomaly is shifted towards higher temperature. A similar scenario was proposed by Biljakovic et al [6] for the glass transition in doped TaS 3 CDW compounds.…”

“…Depending on the temperature, two qualitatively different regimes have been found for the CDW dynamics [3,4]: above ∼50 K, the nonlinear conductivity above a small depinning threshold field (∼10-100 mV cm −1 ) arises from a deformable CDW with strong damping by normal carriers; below ∼50 K, the CDW dynamics, in the insulating state, is essentially that of a rigid body with a very small damping above an abrupt large threshold field (∼10 V cm −1 ). This change in the CDW rigidity is accompanied by anomalies in a large number of properties such as: low frequency dielectric response [5][6][7][8][9], thermally stimulated depolarization current [5,10], unit cell parameters [11], proton channelling [12] and EPR intensity of Mo 5+ lines [13]. No structural phase transition occurs at ∼50 K.…”

Energy Landscape of Charge Excitations in the Boundary Region between Dimer–Mott and Charge Ordered States in Molecular Solids

“…The present demonstrations will shed light on the possible microscopic understanding of experimental observations 2,3) of dielectric anomalies seen in the range of 10 KHz based on the familiar microscopic model Hamiltonian for electrons in solids describing the competitions between dimer-Mott and charge ordering which are typical states in the presence of strong correlations in quarter-filled bands. It is to be noted that interesting phenomena observed in specific heat 19,20) and infrared optical measurements 21) are in different energy region from the present studies, though these will be mutually interrelated. Finally, we give brief comments on the relevance of the present scheme to experimentally observed KHz dynamics in a mono-axial chiral helimagnet 22,23) near the boundary of magnetic phase transitions.…”