Physics – Condensed Matter
Scientific paper
1996-09-25
Physics
Condensed Matter
7 pages, revtex, 7 Postscript figures
Scientific paper
10.1007/BF02548136
The microscopic description of the spin-Peierls transition in pure and doped CuGeO_3 is developed taking into account realistic details of crystal structure. It it shown that the presence of side-groups (here Ge) strongly influences superexchange along Cu-O-Cu path, making it antiferromagnetic. Nearest-neighbour and next-nearest neighbour exchange constants $J_{nn}$ and $J_{nnn}$ are calculated. Si doping effectively segments the CuO_2-chains leading to $J_{nn}(Si)\simeq0$ or even slightly ferromagnetic. Strong sensitivity of the exchange constants to Cu-O-Cu and (Cu-O-Cu)-Ge angles may be responsible for the spin-Peierls transition itself (``bond-bending mechanism'' of the transition). The nature of excitations in the isolated and coupled spin-Peierls chains is studied and it is shown that topological excitations (solitons) play crucial role. Such solitons appear in particular in doped systems (Cu_{1-x}Zn_xGeO_3, CuGe_{1-x}Si_xO_3) which can explain the $T_{SP}(x)$ phase diagram.
Geertsma Wiebe
Khomskii Daniel
Mostovoy Maxim
No associations
LandOfFree
Elementary excitations, exchange interaction and spin-Peierls transition in CuGeO$_3$ does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Elementary excitations, exchange interaction and spin-Peierls transition in CuGeO$_3$, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Elementary excitations, exchange interaction and spin-Peierls transition in CuGeO$_3$ will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-461074