H. D. Cornean
On the essential spectrum of two dimensional periodic magnetic Schroedinger operators
(397K, postscript)

ABSTRACT.   For two dimensional Schr\"{o}dinger operators with a nonzero magnetic field perturbed by 
an infinite number of periodically disposed, long range magnetic and electric wells, it is 
proven that when the inter-well distance ($R$) goes to infinity, the essential spectrum near 
the eigenvalues of the "one well Hamiltonian" is located in mini-bands whose width is 
shrinking faster than any exponential with $R$. This should be compared with our previous 
result [4], which stated that in the case of compactly supported wells, the mini-bands 
shrink Gaussian like with $R$.