Abstract
We study a spin-Peierls gap and a bound and a resonant states of two magnetic excitations in Cu 1- x Zn x GeO 3 and CuGe 1- y Si y O 3 . Breakdown of the selection rule in the doped samples enables us to observe the spin-Peierls gap excitation in the first-order Raman process. It is found that this excitation shifts to lower frequency and merges into the tail of the elastic scattering together with its line broadening with increasing dopant concentration. The bound state of a particle-hole pair is observed just below the bottom of the second-order Raman band in pure CuGeO 3 . It changes into a resonant state and disappears rapidly as the concentration of the dopant is increased, owing to the weakening of attractive interaction and the extreme increase of the dampings of the magnetic excitations. These features are demonstrated theoretically by using Green's function.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
