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.

Incommensurate modulated phases of the NbxTa1-xTe4 charge density wave system

1992 ◽  
Vol 50 (1) ◽  
pp. 58-59
Author(s):  
S. Ritchie ◽  
J. C. Bennett ◽  
A. Prodan ◽  
F.W. Boswell ◽  
J.M. Corbett
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Direct Evidence ◽  
Density Wave ◽  
Wave System ◽  
Modulated Phases ◽  
Metal Atoms ◽  
Incommensurate Modulation ◽  
End Members ◽  
Modulation Wave Vector

A continuous sequence of compounds having composition NbxTa1-xTe4; 0 ≤ x ≤ 1 have been studied by electron diffraction and microscopy. Previous studies have shown that the end members of the series, TaTε4 and NbTε4 possess a quasi-one-dimensional character and exhibit charge density wave (CDW) distortions. In these compounds, the subcell structure is tetragonal with axes (a × a × c) and consists of the metal atoms (Nb or Ta) centered within an extended antiprismatic cage of Te atoms. At room temperature, TaTε4 has a commensurate modulation structure with a 2a × 2a × 3c unit cell. In NbTε4, an incommensurate modulation with × ∼ 16c axes is observed. Preliminary studies of the mixed compounds NbxTα1-xTε4 showed a discontinuous jump of the modulation wave vector commensurate to incommensurate when the Nb dopant concentration x, exceeded x ≃ 0.3, In this paper, the nature of the compositional dependence of is studied in greater detail and evidence is presented for a stepwise variation of . This constitutes the first direct evidence for a Devil's staircase in CDW materials.

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.

Spectroscopic signatures of phase transitions in a charge-density-wave system: 1T-TaS2

1992 ◽  
Vol 46 (12) ◽  
pp. 7407-7412 ◽  
Author(s):  
B. Dardel ◽  
M. Grioni ◽  
D. Malterre ◽  
P. Weibel ◽  
Y. Baer ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave System ◽  
A Charge ◽  
Spectroscopic Signatures

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.

Achieving Room‐Temperature Charge Density Wave in Transition Metal Dichalcogenide 1 T ‐VSe 2

2020 ◽  
Vol 6 (5) ◽  
pp. 1901427
Author(s):  
Jiajia Feng ◽  
Resta A. Susilo ◽  
Bencheng Lin ◽  
Wen Deng ◽  
Yanju Wang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Density Wave ◽  
Transition Metal Dichalcogenide

The angular magnetothermoelectric power of a charge density wave system

2012 ◽  
Vol 24 (26) ◽  
pp. 265502 ◽  
Author(s):  
D Krstovska ◽  
E S Choi ◽  
E Steven ◽  
J S Brooks
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave System ◽  
A Charge

Complete excitation spectrum for a charge-density-wave system

1987 ◽  
Vol 36 (12) ◽  
pp. 6708-6711 ◽  
Author(s):  
M. S. Sherwin ◽  
A. Zettl ◽  
P. L. Richards
Keyword(s):  
Charge Density ◽  
Excitation Spectrum ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave System ◽  
A Charge
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