Tunneling Spectra of NbSe3 in Magnetic Fields

1998 ◽  
Vol 12 (24) ◽  
pp. 1013-1019
Author(s):  
He Haifeng ◽  
Wang Yunping ◽  
Li Shanlin ◽  
Jing Xiunian ◽  
Li Guohong ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Charge Density ◽  
Applied Magnetic Field ◽  
Charge Density Wave ◽  
Density Wave ◽  
Mean Field ◽  
Fermi Surface Nesting ◽  
The Mean ◽  
Gap Parameter

The charge density wave gaps of NbSe 3 have been carefully determinated by tunneling spectroscopy. In contrast to earlier work, the gap parameter associated with the 59 K transition obtained in the present measurements is very close to the mean field value. The gap structures for both the 145 K and 59 K transitions are found to be essentially independent of the applied magnetic field H. The present findings strongly suggest that the anomalous magnetotransport properties of the material originate from some other mechanism than a H-induced improvement of Fermi surface nesting.

Thermopower behavior inLa2Mo2O7: A possible charge-density-wave system with partial Fermi-surface nesting

1989 ◽  
Vol 40 (13) ◽  
pp. 9312-9314 ◽  
Author(s):  
K. Surendranath ◽  
C. Bansal ◽  
M. Greenblatt ◽  
W. H. McCarroll
Keyword(s):  
Fermi Surface ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave System ◽  
Fermi Surface Nesting

scholarly journals Fermi surface nesting and charge-density wave formation in rare-earth tritellurides

2005 ◽  
Vol 71 (8) ◽  
Author(s):  
J. Laverock ◽  
S. B. Dugdale ◽  
Zs. Major ◽  
M. A. Alam ◽  
N. Ru ◽  
...  
Keyword(s):  
Rare Earth ◽  
Fermi Surface ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Formation ◽  
Fermi Surface Nesting

scholarly journals Colossal Magnetoresistance in Ln1-x Ax MnO3 Perovskites

1999 ◽  
Vol 52 (2) ◽  
pp. 155 ◽  
Author(s):  
J. B. Goodenough
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Applied Magnetic Field ◽  
Charge Density Wave ◽  
Colossal Magnetoresistance ◽  
Density Wave ◽  
Orthorhombic Phase ◽  
Orbital Ordering ◽  
Static Charge ◽  
O Phase

In the Ln1-xAxMnO3 pseudoperovskites in which Ln is a lanthanide and A an alkaline-earth atom, an intrinsic colossal magnetoresistance (CMR) occurs in an O-orthorhombic phase near an O′-orthorhombic/O-orthorhombic phase boundary. For a fixed ratio Mn(IV)/Mn = 0·3, the transition through the O phase from localised-electron behaviour and orbital ordering in the O′ phase to itinerant-electron behaviour in an R-rhombohedral phase occurs with increasing geometric tolerance factor t ≡ ⟨A-O⟩/√2⟨Mn-O⟩, where ⟨A-O⟩ and ⟨Mn-O⟩ are mean equilibrium bond lengths. The CMR occurs in the temperature interval Tc ≤ T < Ts where there is a segregation, via cooperative oxygen displacements, into a Mn(IV)-rich ferromagnetic phase imbedded in a paramagnetic phase. The volume of the ferromagnetic, more conductive clusters increases from below to beyond a percolation threshold in response, above Tc, to an applied magnetic field and, below Tc, to a Weiss molecular field. In the O phase, the magnetic transition at Tc decreases on the exchange of 18O/16O and increases under hydrostatic pressure. Charge and orbital ordering below a Tco ≤ Tc is found in compositions with x ≈ ⅛ or x ≈ ½. With x ≈ ½, the charge-ordered phase CE is tetragonal and antiferromagnetic. An applied magnetic field stabilises the ferromagnetic, conductive phase relative to the insulator phase CE to give a second type of intrinsic CMR. For x ≈ 0·3, there is no static charge and orbital ordering; but for smaller t, strong electron-lattice coupling gives a ‘bad metal’ behaviour below Tc indicative of a dynamic phase segregation as in a traveling charge-density wave. In La1-xCaxMnO3 with ½ ≤ x ≤ ⅞, segregation of the CE x = 0·5 phase and the all-Mn(IV) x = 1 phase has been reported to take the form of a static charge-density wave. The origins of this complex behaviour are discussed.

Phonon Dispersion and Electronic Structure In Quasi-one- Dimensional Layered Ta2NiSe7 Single Crystal

2020 ◽  
Author(s):  
Haiping Chen ◽  
Zhongti Sun
Keyword(s):  
Electronic Structure ◽  
Fermi Surface ◽  
Single Crystal ◽  
Charge Density ◽  
Charge Density Wave ◽  
Phonon Dispersion ◽  
Density Wave ◽  
Layered Systems ◽  
One Dimensional ◽  
Fermi Surface Nesting

The formation mechanism of charge density wave (CDW) order in layered systems was belived to arise from phonon-electron coupling and electronic structure instability induced by Fermi surface nesting. Herein, we...

Effect of an applied magnetic field on the charge-density-wave carrier concentration inNbSe3

1991 ◽  
Vol 43 (9) ◽  
pp. 7254-7262 ◽  
Author(s):  
T. M. Tritt ◽  
A. C. Ehrlich ◽  
D. J. Gillespie ◽  
G. X. Tessema
Keyword(s):  
Magnetic Field ◽  
Charge Density ◽  
Carrier Concentration ◽  
Applied Magnetic Field ◽  
Charge Density Wave ◽  
Density Wave

Hidden Fermi Surface Nesting and Charge Density Wave Instability in Low-Dimensional Metals

Science ◽  
1991 ◽  
Vol 252 (5002) ◽  
pp. 96-98 ◽  
Author(s):  
M. -H. WHANGBO ◽  
E. CANADELL ◽  
P. FOURY ◽  
J. -P. POUGET
Keyword(s):  
Fermi Surface ◽  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Instability ◽  
Fermi Surface Nesting ◽  
Low Dimensional
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