Plateaux in magnetization curves and spin gaps in frustrated magnets and spin ladders

Sketch of a magnetization curve (<M> versus h) of a 3-leg ladder, showing a plateau at one third the saturation value.

One issue that fascinates me is the appearance of plateaux in magnetization curves. Such phenomena mean that the global magnetization of the sample gets quantized. Such quantization phenomena are interesting both from the mathematical point of view (one may speculate about some kind of topological quantization) but also for applications. Concerning the latter, one may dream about a solid-state realization of a quantum mechanical computer which would use such global quantization phenomena.

However, what we have done is not related to quantum mechanical computers (at least not yet), and also the topological interpretation remains speculative so far.

I'm sorry that I did not have time to write a nice abstract of what we have really done.

If you are interested in magnetization curves of spin ladders, you can take a look at

this letter or
this longer paper or
another long paper on zig-zag ladders.
In addition, there are two posters on spin ladders (which differ from the above in that they have colour pictures and a different presentation):
- A first poster with emphasis on numerics and field-theory,
- A second poster with emphasis on the strong-coupling region.
Some supplemetary software for the XXZ-chain in a magnetic field can be accessed via this experimental WWW page (backup at this URL).

Other situations where I have investigated magnetization plateaux are:

The stacked triangular lattice antiferromagnet CsCuCl₃:
- A first poster (in German) and
- a second more recent poster in English.
- And finally the paper.
A paper on polymerized quantum spin chains.
A paper on two-dimensional antiferromagnets.

May, 9th, 2000,
a.honecker@tu-bs.de