... | ... | @@ -17,28 +17,28 @@ function (KKR-GF) method, space is partitioned into nonoverlapping |
|
|
regions surrounding the atoms, labeled $i$. These regions are taken as
|
|
|
spherical in the atomic sphere approximation (ASA), and the KS potential
|
|
|
is also assumed to be spherical around each atom,
|
|
|
$`V\^{\text{KS}}_i(r)$`, with $`r = |\vec{r}\,|$` and $`\hat{r} =
|
|
|
\vec{r}/r$`. Then the KS GF is expressed in terms of energy-dependent
|
|
|
$V\^{\text{KS}}_i(r)$, with $r = |\vec{r}\,|$ and $\hat{r} =
|
|
|
\vec{r}/r$. Then the KS GF is expressed in terms of energy-dependent
|
|
|
scattering solutions for each atomic potential,
|
|
|
$`R_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$` and
|
|
|
$`H_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$`, which are products of
|
|
|
radial functions and (real) spherical harmonics, for each spin $`\sigma
|
|
|
= \;\uparrow,\,\downarrow$` and angular momentum $`L = (\ell,m)$`.
|
|
|
$`R_{i\ell}\^\sigma(r;E)$` is regular at the center of the ASA
|
|
|
sphere, and $`H_{i\ell}\^\sigma(r;E)$` diverges there.
|
|
|
$R_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$ and
|
|
|
$H_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$, which are products of
|
|
|
radial functions and (real) spherical harmonics, for each spin $\sigma
|
|
|
= \;\uparrow,\,\downarrow$ and angular momentum $L = (\ell,m)$.
|
|
|
$R_{i\ell}\^\sigma(r;E)$ is regular at the center of the ASA
|
|
|
sphere, and $H_{i\ell}\^\sigma(r;E)$ diverges there.
|
|
|
|
|
|
The Korringa-Kohn-Rostoker Green function is given by
|
|
|
```math
|
|
|
G_{ij}^\sigma(\vec{r}\,,\vec{r}\,';E) &=& \sum_{LL'}Y_L(\hat{r}) \big(\sqrt{E}\,R_{i\ell}^\sigma(r_<;E)\,H_{i\ell}^\sigma(r_>;E)\delta_{ij}\delta_{LL'} \nonumber\
|
|
|
&&\hspace{-4em} + R_{i\ell}^\sigma(r;E)\,G^{\sigma,\text{str}}_{iL,jL'}(E)\,R_{j\ell'}^\sigma(r';E)\big) Y_{L'}(\hat{r}') \; ,
|
|
|
```
|
|
|
where $`r_\< = \min(r,r\')$` and $`r_\> =
|
|
|
\max(r,r\')$`, and $`G\^{\sigma,\text{str}}_{iL,jL\'}(E)$` is the
|
|
|
where $r_\< = \min(r,r\')$ and $r_\> =
|
|
|
\max(r,r\')$, and $G\^{\sigma,\text{str}}_{iL,jL\'}(E)$ is the
|
|
|
structural GF, describing backscattering effects.
|
|
|
|
|
|
Near the Fermi energy ($`E_\text{F}$`) one may approximate
|
|
|
$`R_{i\ell}\^\sigma(r;E) \approx
|
|
|
R_{i\ell}\^\sigma(r;E_\text{F})$`.
|
|
|
Near the Fermi energy ($E_\text{F}$) one may approximate
|
|
|
$R_{i\ell}\^\sigma(r;E) \approx
|
|
|
R_{i\ell}\^\sigma(r;E_\text{F})$.
|
|
|
|
|
|
## Susceptibility
|
|
|
|
... | ... | @@ -51,9 +51,9 @@ The transverse magnetic Kohn-Sham susceptibility is given by |
|
|
& & \hspace{-6em}\Big(G_{ij}^{\bar\sigma}(\vec{r}\,,\vec{r}\,';E+\omega+\mathrm{i} 0)\,\text{Im}\,G_{ji}^{\sigma}(\vec{r}\,',\vec{r}\,;E) + \text{Im}\,G_{ij}^{\bar\sigma}(\vec{r}\,,\vec{r}\,';E)\,G_{ji}^{\sigma}(\vec{r}\,',\vec{r}\,;E-\omega-\mathrm{i} 0)\Big) \, .
|
|
|
```
|
|
|
|
|
|
Here, $`\chi\^{\uparrow\downarrow}$` and
|
|
|
$`\chi\^{\downarrow\uparrow}$` correspond to $`\chi\^{+-}$` and
|
|
|
$`\chi\^{-+}$`, respectively.
|
|
|
Here, $\chi\^{\uparrow\downarrow}$ and
|
|
|
$\chi\^{\downarrow\uparrow}$ correspond to $\chi\^{+-}$ and
|
|
|
$\chi\^{-+}$, respectively.
|
|
|
|
|
|
### Dyson-like equation
|
|
|
|
... | ... | |