This week's seminar

[CM ICTP - Trieste]

CONDENSED MATTER AND STATISTICAL PHYSICS SECTION
	
Informal Seminar on
Disorder and strong electron correlations



Thursday, 4 May    -    11:00 a.m.




Room 239,  Main Bldg.- II floor




N. SHANNON  ( University of Bristol )




"How to have fun with  two-dimensional frustrated ferromagnets..."


Abstract

The theoretical study of  two-dimensional "spin liquids''  --- quantum 
magnets which remain disordered at the very lowest temperatures --- has 
mostly been confined to models with competing or frustrated 
antiferromagnetic (AF) interactions. The resulting ground states 
typically involve strong singlet bonds between spins, which give rise 
to a gap in the spin excitation spectrum.  None the less, the best 
characterized experimental realization of a spin liquid is believed to 
occur in two--dimensional films of solid $^3$He, where the interactions 
between spins are predominantly ferromagnetic (FM), and the resulting 
state is gapless.  Here we consider whether the breakdown of long 
ranged FM order offers a new route unconventional magnetic ground 
states in two dimensions, considering in detail the case of the square 
lattice frustrated ferromagnet.