|
|
| Competition: Electronic energy vs. Lattice
(elastic) energy |
|
| (recall
that band electrons move in a weak, periodic potential) |
|
| Elastic energy
is increased ~ D2 |
| At low
temperature dimerization always favorable |
|
|
| kFermi
is still p/2a and since d = 2p/k
, |
|
| d = 4a (charge density wave) |
|