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3 votes
2 answers
313 views

Explanation of massive Goldstone modes

I'm solving this exercise with a Heisenberg Hamiltonean in linear spin-wave theory and at some point we are asked to compute the dispersion relation at $k=0$, which leads me to finding two different ...
Rye's user avatar
  • 548
0 votes
0 answers
121 views

Is it possible to construct an operator for $z$-component of spin for a 2D system?

Let's say we have an arrangement of spins in 2D space (as given in the below picture). Assume that the $z$-axis is out of the plane and a spin (circled in red) makes an angle $\theta$ with the $x$-...
Luqman Saleem's user avatar
0 votes
0 answers
105 views

Exchange stiffness for HCP

I am studying the exchange interaction, which can be described with the Heisenberg Hamiltonian: $\hat{H} = -\sum_{i,j}J_{ij}\hat{\mathbf{S_i}}\cdot \hat{\mathbf{S_j}}$ In the framework of constant ...
mickeymar's user avatar