 
FIZIKA A 14 (2005) 1 , 4774
OPTICAL PROPERTIES WITHIN THE Q1D MULTIBAND MODELS  THE TRANSVERSE
EQUATION OF MOTION APPROACH
IVAN KUPČIĆ and SLAVEN BARIŠIĆ
Department of Physics, Faculty of Science, P.O.B. 331, HR10 002 Zagreb,
Croatia
Email addresses: kupcic@phy.hr, sbarisic@phy.hr
Received 3 March 2004; Accepted 27 June 2005
Online 21 October 2005
The electrodynamic features of the multiband model are examined using the transverse
equation of motion approach in order to give the explanation of several longstanding
problems. It turns out that the exact summation of the most singular terms in powers of 1/w^{n} leads to the total optical conductivity which, in the
zerofrequency limit, reduces to the results of the Boltzmann equation, both for the
metallic and semiconducting twoband regime. The detailed calculations have been carried
out for the quasionedimensional (Q1D) twoband model corresponding to the imperfect
chargedensitywave (CDW) nesting. It is also shown that the results of the present
treatment of the impurityscattering processes for the DC conductivity of the ordered CDW
state are in agreement with the experimental observation. Finally, the DC and optical
conductivity are calculated numerically for a few typical Q1D cases.
PACS numbers: 78.20.e, 72.20i, 71.30+h
UDC 538.958
Keywords: optical properties, CDW systems, multiband models, transverse response
theory
