Linker IT Software
Google
Web www.oraxcel.com
menubar-top-links menubar-top-rechts
Home Help Search Login
Welcome, Guest. Please Login.
SQL*XL: Database to Excel bridge litLIB: Excel power functions pack ExcelLock: Locking and securing your valuable Excel spreadsheets encOffice: Protect your Excel file easy and safe encOffice: Protect your Excel file easy and safe
Pages: 1
Peierls transition (Read 2339 times)
Gerrit-Jan Linker
YaBB Administrator
*****




Posts: 75
Peierls transition
19.05.12 at 11:55:18
 
Peierls transition
 
Peierls' Theorem: a one-dimensional equally spaced chain with one electron per ion is unstable.
 
When a lattice distortion causes the period to double from a to 2a, new band gaps will be introduced at multiples of k=pi/(2a).  
 
Around k=pi/(2a), where the new band gap had formed, the band energy of the lowest energy band is lowered compared to the undimerised system without the band gap. These electrons with a k around pi/(2a) have lowered their energy and this is the souce of the Peierls effect.
 
The lattice distortion become energetically favourable when the energy savings due to the new band gaps outweigh the elastic energy cost of rearranging the ions. Therefore the Peierls effect will be noticed when the electrons are arranged close to their ground state, i.e. when thermal excitation is low, i.e. at low temperatures.
 
Source:
http://en.wikipedia.org/wiki/Peierls_transition
 
In the following papers Peierls and Frohlich showed that a one-dimensional electron system in a deformable lattice is unstable against a modulation of the lattice of wavenumber 2kF (kF  is the Fermi wavenumber):
Peierls, R. E., 1955,  Quantum Theory of Solids (London: Oxford University Press), p.108;  
Frohlich, H., 1954, Proc. R. Soc. A, 223, 296.  
Back to top
 
« Last Edit: 14.10.12 at 09:52:07 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
Linker IT Software
Email WWW Gerrit-Jan Linker   IP Logged
Pages: 1