[Wien] Antiferromagnetic Calculation With Orbital Potentials

[Hua Wu]

Is the Yb 5d band so broad that its relatively small exchange splitting
can not stabilize a 'local' 5d moment ? Are you sure that in your first case,
the 2uB comes from both Yb 4f and 5d ?  -- H. Wu
 
On Tuesday 12 May 2009 16:09, David Tompsett wrote:
> Dear All,
>              I am studying the magnetic ground state of a metallic
> system. The magnetic atoms are Yb, and I am localizing the 4f moment
> using an orbital potential, as well as applying spin-orbit coupling.
>
> I have a question about the behaviour of the spin moments depending on
> my input to case.inst
> Firstly, I set the starting spins such that the 5d electron and 4f hole
> have a net spin and are flipped between the two Yb atoms:
> Yb
> Xe 4
> 4, 3,3.0  N
> 4, 3,3.0  N
> 4,-4,4.0  N
> 4,-4,3.0  N
> 5, 2,1.0  N
> 5, 2,0.0  N
> 6,-1,1.0  N
> 6,-1,1.0  N
>
> Yb2
> Xe 4
> 4, 3,3.0  N
> 4, 3,3.0  N
> 4,-4,3.0  N
> 4,-4,4.0  N
> 5, 2,0.0  N
> 5, 2,1.0  N
> 6,-1,1.0  N
> 6,-1,1.0  N
> In this case the moments between the two Yb atoms go towards spin
> moments of +2u and -1u during the convergence. Not an antiferromagnetic
> solution.
>
> Second, I set the 6s spin to 0.5 up and 0.5 down( ie. not net spin) in
> case.inst:
> Yb
> Xe 4
> 4, 3,3.0  N
> 4, 3,3.0  N
> 4,-4,4.0  N
> 4,-4,3.0  N
> 5, 2,0.5  N
> 5, 2,0.5  N
> 6,-1,1.0  N
> 6,-1,1.0  N
>
> Yb2
> Xe 4
> 4, 3,3.0  N
> 4, 3,3.0  N
> 4,-4,3.0  N
> 4,-4,4.0  N
> 5, 2,0.5  N
> 5, 2,0.5  N
> 6,-1,1.0  N
> 6,-1,1.0  N
> Then, a stable antiferromagnetic solution was found.
>
> Questions:
> 1) Does the different behaviour occur because I am only applying my
> orbital potential to the 4f states and not 5d?
>
> 2) Is there some other physics to explain this? Is there something that
> I can check to diagnose the behaviour in the first case?
>
> Thanks,
> David.