scholarly journals Huge values of room-temperature dielectric constants in pellets of poly(3-methylthiophene)

2004 ◽  
Vol 19 (7) ◽  
pp. 2068-2071
Author(s):  
S. Moraes ◽  
L. Walmsley ◽  
E.C. Pereira ◽  
A.A. Correa
Keyword(s):  
Dielectric Constant ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Low Frequency ◽  
Temperature Data ◽  
Dielectric Constants ◽  
Wave Characteristic ◽  
Rc Circuit ◽  
A Charge

Room temperature data of impedance and phase angle in pellets of electrochemically synthesized ClO4− doped poly(3-methylthiophene) (P3MT) were analyzed assuming the sample being represented by a parallel resistor-capacitor (RC) circuit or by a series RC circuit. The last assumption proved to be the correct one, and to confirm it we use the sample as the RC component of a resistor-capacitor-inductor series resonator. We discuss the possibility of this RC series behavior to be due to a charge-density wave characteristic also evidenced from the huge values of the low-frequency dielectric constant of the system.

scholarly journals Ultrafast manipulation of mirror domain walls in a charge density wave

2018 ◽  
Vol 4 (10) ◽  
pp. eaau5501 ◽  
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.

A charge-density-wave oscillator based on an integrated tantalum disulfide–boron nitride–graphene device operating at room temperature

2016 ◽  
Vol 11 (10) ◽  
pp. 845-850 ◽  
Author(s):  
Guanxiong Liu ◽  
Bishwajit Debnath ◽  
Timothy R. Pope ◽  
Tina T. Salguero ◽  
Roger K. Lake ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Wave Oscillator ◽  
A Charge

The Effects of Transition Metal Substitutions in the NbTe4-TaTe4 Charge-Density Wave System

1992 ◽  
Vol 45 (9) ◽  
pp. 1363 ◽  
Author(s):  
JC Bennett ◽  
FW Boswell ◽  
A Prodan ◽  
JM Corbett ◽  
S Ritchie
Keyword(s):  
Transition Metal ◽  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Dark Field ◽  
Wave System ◽  
Incommensurate Modulation ◽  
High Concentrations ◽  
A Charge

At room temperature, the structures of TaTe4 and NbTe4 are modulated by the presence of a charge-density wave which in the former compound is commensurate with the parent lattice and in the latter incommensurate. In addition, a series of incommensurate mixed crystals ( Tal-xNbx )Te4 (0 ≤ x ≤) exist in which the modulation wavevector increases as a function of x. In this paper, we report the occurrence of a systematic variation in the period of the charge-density wave upon substitution of the transition metal elements Ti, Zr or V for either Nb or Ta. Electron diffraction experiments reveal that, in TaTe4, substitutions of Group 4 elements Ti and Zr result in an incommensurate modulation with a decrease in the modulation wavevector q. In NbTe4, substitutions of Ti or Zr also reduce q, in this case towards the commensurate value, and, at sufficiently high concentrations, a commensurate phase is stabilized at room temperature. Vanadium substitutions in NbTe4 result in a slight increase in q. Satellite dark-field images reveal the presence of defects in the modulation structures of the doped crystals. The above results are discussed in terms of the factors which determine the charge-density wave periodicity in the NbTe4-TaTe4 system.

scholarly journals Robust charge-density wave strengthened by electron correlations in monolayer 1T-TaSe2 and 1T-NbSe2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuki Nakata ◽  
Katsuaki Sugawara ◽  
Ashish Chainani ◽  
Hirofumi Oka ◽  
Changhua Bao ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Charge Density ◽  
Electron Correlation ◽  
Charge Density Wave ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Density Wave ◽  
Mott Insulator ◽  
Transition Metal Dichalcogenide ◽  
A Charge

AbstractCombination of low-dimensionality and electron correlation is vital for exotic quantum phenomena such as the Mott-insulating phase and high-temperature superconductivity. Transition-metal dichalcogenide (TMD) 1T-TaS2 has evoked great interest owing to its unique nonmagnetic Mott-insulator nature coupled with a charge-density-wave (CDW). To functionalize such a complex phase, it is essential to enhance the CDW-Mott transition temperature TCDW-Mott, whereas this was difficult for bulk TMDs with TCDW-Mott < 200 K. Here we report a strong-coupling 2D CDW-Mott phase with a transition temperature onset of ~530 K in monolayer 1T-TaSe2. Furthermore, the electron correlation derived lower Hubbard band survives under external perturbations such as carrier doping and photoexcitation, in contrast to the bulk counterpart. The enhanced Mott-Hubbard and CDW gaps for monolayer TaSe2 compared to NbSe2, originating in the lattice distortion assisted by strengthened correlations and disappearance of interlayer hopping, suggest stabilization of a likely nonmagnetic CDW-Mott insulator phase well above the room temperature. The present result lays the foundation for realizing monolayer CDW-Mott insulator based devices operating at room temperature.

scholarly journals Ultrafast formation of domain walls of a charge density wave in SmTe3

2021 ◽  
Vol 103 (5) ◽  
Author(s):  
M. Trigo ◽  
P. Giraldo-Gallo ◽  
J. N. Clark ◽  
M. E. Kozina ◽  
T. Henighan ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Domain Walls ◽  
Density Wave ◽  
A Charge

Ultrafast switching to an insulating-like metastable state by amplitudon excitation of a charge density wave

2021 ◽  
Author(s):  
Naotaka Yoshikawa ◽  
Hiroki Suganuma ◽  
Hideki Matsuoka ◽  
Yuki Tanaka ◽  
Pierre Hemme ◽  
...  
Keyword(s):  
Charge Density ◽  
Metastable State ◽  
Charge Density Wave ◽  
Density Wave ◽  
Ultrafast Switching ◽  
A Charge

scholarly journals Ultrafast spot-profile LEED of a charge-density wave phase transition

2021 ◽  
Vol 118 (22) ◽  
pp. 221603
Author(s):  
G. Storeck ◽  
K. Rossnagel ◽  
C. Ropers
Keyword(s):  
Phase Transition ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Phase ◽  
Charge Density Wave Phase ◽  
A Charge

An experimentalist's view of the galvanomagnetic and thermomagnetic properties of potassium

1982 ◽  
Vol 60 (5) ◽  
pp. 679-686 ◽  
Author(s):  
R. Fletcher
Keyword(s):  
Experimental Investigation ◽  
Charge Density ◽  
Charge Density Wave ◽  
High Field ◽  
Density Wave ◽  
The Other ◽  
Detailed Structure ◽  
Precise Nature ◽  
A Charge ◽  
Thermomagnetic Properties

This paper provides a brief survey of the experimental and theoretical situation regarding the galvano- and thermomagnetic properties of potassium viewed within the context of the behaviour of other metals. Most of the data are consistent with various sample imperfections as being the major source of the anomalies that are found. However, the precise nature of the imperfections and the mechanism by which the imperfections produce the anomalies are not yet known. It is argued that the recently discovered detailed structure in the high field induced torque of K should be subjected to intensive experimental investigation before drawing any conclusions with regards to the possible presence of a charge density wave; the other magnetotransport properties offer little evidence either for or against such a possibility.

CHARGE DENSITY WAVE TRANSITIONS IN TWO-DIMENSIONAL TRANSITION METAL BRONZES AND OXIDES

1993 ◽  
Vol 07 (23n24) ◽  
pp. 3973-4003 ◽  
Author(s):  
P. FOURY ◽  
J.P. POUGET
Keyword(s):  
Transition Metal ◽  
Charge Density ◽  
Ground State ◽  
Charge Density Wave ◽  
Density Wave ◽  
Electron Localization ◽  
Two Dimensional ◽  
Fermi Surfaces ◽  
A Charge ◽  
Structural Instabilities

The structural instabilities towards the formation of a charge density wave (CDW) ground state exhibited by several layered Mo and W bronzes and oxides are reviewed. It is shown that in these two-dimensional (2D) metals, including the purple bronzes A x Mo 6 O 17 (A=K, Na, Tl; x≈1), the γ and η phases of MO 4 O 11 and the monophosphate tungsten bronzes with pentagonal tunnels ( PO 2)4 ( WO 3)2m(m=4, 6, 7), the CDW instability can be associated with particular chains of MoO 6 or WO 6 octahedra of the ReO 3 type slabs along which there is a strong overlap of the t 2g orbitals. The CDW critical wave vectors of the purple bronzes, Mo 4 O 11 and the tungsten bronzes with m=4 and 6 lead to a common nesting between differently oriented 1D Fermi surfaces. It is suggested that the anharmonic CDW modulation, which occurs in the tungsten bronzes with m≥7, could be the structural fingerprint of electron localization effects.

Sign in / Sign up

Export Citation Format

Share Document