... | ... | @@ -12,13 +12,13 @@ links: |
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Starting point: Schrödinger equation
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```math
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\mathcal{H}\|\psi\rangle = E\|\psi\rangle
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\mathcal{H}|\psi\rangle = E|\psi\rangle
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```
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This can formally be written with the Green
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function $`\mathcal{G}`$ as
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```math
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(\epsilon -\mathcal{H})\mathcal{G}(\epsilon)=1, \quad \epsilon=E+i\delta,
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\quad \delta\>0
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\quad \delta>0
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```
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Thus by knowing the GF one can extract the
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systems properties, i.e. the expectation value $`\langle
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... | ... | @@ -53,7 +53,7 @@ crystal into three steps: (i) compute the scattering properties of free |
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Lippmann-Schwinger equation, (ii) construct the multiple scattering via
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the structural Green function from systems geometry and (iii) construct
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the Green from the in (i) obtained wavefunctions and single-site
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$`t$`-matrix and the in thep (ii) computed structural GF.
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$`t`$-matrix and the in thep (ii) computed structural GF.
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### (i) Single-site problem
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... | ... | @@ -115,8 +115,8 @@ positions vanish, i.e. $`\Delta t=0`$. This allows us to embed the |
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impurity in a finite real space cluster into the host system. The
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calculation is then done as follows.
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- Compute the host systems Green function and write out the structural Green function as well as the single-site $`t`$ matrix of the host $`t_{\mathrm{host}}`$.
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- From the impurity potential compute the $t$-matrix of the impurity and construct $`\Delta t=t_{\mathrm{host}}-t_{\mathrm{imp}}`$
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- Solve the impurity Dyson equation: $`\underline{\underline{G}}=\underline{\underline{G}}_{\mathrm{host}}+\underline{\underline{G}}_{\mathrm{host}}\Delta t\underline{\underline{G}}`$
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- Compute the new impurity potential from the Green function and update the input potential
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- Repeat steps 2.-4. until the impurity potential converges |
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* Compute the host systems Green function and write out the structural Green function as well as the single-site $`t`$ matrix of the host $`t_{\mathrm{host}}`$.
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* From the impurity potential compute the $`t`$-matrix of the impurity and construct $`\Delta t=t_{\mathrm{host}}-t_{\mathrm{imp}}`$
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* Solve the impurity Dyson equation: $`\underline{\underline{G}}=\underline{\underline{G}}_{\mathrm{host}}+\underline{\underline{G}}_{\mathrm{host}}\Delta t\underline{\underline{G}}`$
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* Compute the new impurity potential from the Green function and update the input potential
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* Repeat steps 2.-4. until the impurity potential converges |