Impurity-induced modulations in NbSe{sub 3} detected by atomic-force microscopy

Journal Article · Mon May 15 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.51.12975· OSTI ID:74027

Gong, Y; Xue, Q; Drake, D L; Qian, J; Coleman, R V ^[1]

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1. Physics Department, University of Virginia, Charlottesville, Virginia 22901 (United States)

Long-range modulations at room temperature in NbSe{sub 3} doped with interstitial impurities have been observed using both atomic-force microscopy and scanning tunneling microscopy. The wavelength of these modulations is a function of the impurity concentration starting as high as ten unit cells in wavelength and changing through a sequence of wavelengths to a wavelength of two unit cells. These modulations are closely connected to the existence of a strong susceptibility anomaly which induces two charge-density waves (CDW`s) with onset temperatures of 144 and 59 K, respectively. If the CDW`s are quenched above certain critical concentrations, then the room-temperature modulations are also quenched. This general behavior has been observed for eight different interstitial impurities: V, Mn, Cr, Gd, Pd, Fe, Co, and Ni. The impurity-induced modulations are not observed for substitutional impurities such as Ti. In a number of cases interstitial impurities at certain critical concentrations can introduce crystal phases which exhibit a range of electronic properties such as a metal-insulator transition. The presence of the high-temperature modulations has only small effects on CDW formation until the concentration approaches critical values. These effects have been monitored by measuring the temperature dependence of resistance in the range 300--4.2 K. The high-temperature modulations result from long-range impurity screening effects and preferred interstitial impurity sites, in the presence of a complex susceptibility response of the electron gas.

• DOE Contract Number: FG05-84ER45072
• OSTI ID: 74027
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 19 Vol. 51; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHARGE DENSITY
CHROMIUM ADDITIONS
COBALT ADDITIONS
CRYSTAL DOPING
CRYSTAL-PHASE TRANSFORMATIONS
ELECTRIC CONDUCTIVITY
ELECTRONIC STRUCTURE
GADOLINIUM ADDITIONS
INTERSTITIALS
IRON ADDITIONS
MANGANESE ADDITIONS
NICKEL ADDITIONS
NIOBIUM SELENIDES
PALLADIUM ADDITIONS
SCANNING ELECTRON MICROSCOPY
SUBSTOICHIOMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
VANADIUM ADDITIONS