Lattice dynamics of Ti, Co, Tc, and other hcp transition metals

Journal Article · Thu Apr 15 04:00:00 EST 1982 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.25.5122· OSTI ID:5228423

Wakabayashi, N; Scherm, R H; Smith, H G

New phonon-dispersion curves as determined by inelastic neutron-scattering experiments are presented for the hcp metals, Ti, Co, and Tc, along with their theoretical analysis in terms of the phenomenological charge-fluctuations model. The model was also used to reanalyze the phonon data for some other hcp metals, Sc, Y, Zr, and Hf. For all the metals other than Sc and Y it was found that the data could be successfully analyzed only with a dipolar-charge-fluctuation model, in contrast to Nb which required only monopolar terms. For Sc and Y the dispersion curve were satisfactorily analyzed in terms of a third-neighbor Born--von Karman model without any charge-fluctuation terms. The softening of the longitudinal (001) mode near GAMMA observed in some of the metals appears to be closely related to an incipient instability in the electronic system toward the formation of a dipolar charge-density wave. The temperature dependence of the large anomaly in Tc could be reproduced by extremely small changes in one of the parameters of the dipolar-charge-fluctuation model.

• Research Organization: Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5228423
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 25:8; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
COBALT
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELEMENTS
HAFNIUM
HCP LATTICES
HEXAGONAL LATTICES
METALS
PHONONS
QUASI PARTICLES
SCANDIUM
TECHNETIUM
TITANIUM
TRANSITION ELEMENTS
YTTRIUM
ZIRCONIUM