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Update theory (inline math $`x$` --> $x$ remove backticks)
authored
Jan 30, 2025
by
Johannes Wasmer
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@@ -17,28 +17,28 @@ function (KKR-GF) method, space is partitioned into nonoverlapping
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@@ -17,28 +17,28 @@ function (KKR-GF) method, space is partitioned into nonoverlapping
regions surrounding the atoms, labeled $i$. These regions are taken as
regions surrounding the atoms, labeled $i$. These regions are taken as
spherical in the atomic sphere approximation (ASA), and the KS potential
spherical in the atomic sphere approximation (ASA), and the KS potential
is also assumed to be spherical around each atom,
is also assumed to be spherical around each atom,
$
`
V\^{\text{KS}}_i(r)$
`
, with $
`
r = |\vec{r}\,|$
`
and $
`
\hat{r} =
$V
\^
{
\t
ext{KS}}_i(r)$, with $r = |
\v
ec{r}
\,
|$ and $
\h
at{r} =
\vec{r}/r$
`
. Then the KS GF is expressed in terms of energy-dependent
\v
ec{r}/r$. Then the KS GF is expressed in terms of energy-dependent
scattering solutions for each atomic potential,
scattering solutions for each atomic potential,
$
`
R_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$
`
and
$R_{i
\e
ll}
\^\s
igma(r;E)
\,
Y_{L}(
\h
at{r})$ and
$
`
H_{i\ell}\^\sigma(r;E)\,Y_{L}(\hat{r})$
`
, which are products of
$H_{i
\e
ll}
\^\s
igma(r;E)
\,
Y_{L}(
\h
at{r})$, which are products of
radial functions and (real) spherical harmonics, for each spin $
`
\sigma
radial functions and (real) spherical harmonics, for each spin $
\s
igma
= \;\uparrow,\,\downarrow$
`
and angular momentum $
`
L = (\ell,m)$
`
.
=
\;\u
parrow,
\,\d
ownarrow$ and angular momentum $L = (
\e
ll,m)$.
$
`
R_{i\ell}\^\sigma(r;E)$
`
is regular at the center of the ASA
$R_{i
\e
ll}
\^\s
igma(r;E)$ is regular at the center of the ASA
sphere, and $
`
H_{i\ell}\^\sigma(r;E)$
`
diverges there.
sphere, and $H_{i
\e
ll}
\^\s
igma(r;E)$ diverges there.
The Korringa-Kohn-Rostoker Green function is given by
The Korringa-Kohn-Rostoker Green function is given by
```
math
```
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\
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}') \; ,
&&\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_\> =
where $r_
\<
=
\m
in(r,r
\'
)$ and $r_
\>
=
\max(r,r\')$
`
, and $
`
G\^{\sigma,\text{str}}_{iL,jL\'}(E)$
`
is the
\m
ax(r,r
\'
)$, and $G
\^
{
\s
igma,
\t
ext{str}}_{iL,jL
\'
}(E)$ is the
structural GF, describing backscattering effects.
structural GF, describing backscattering effects.
Near the Fermi energy ($
`
E_\text{F}$
`
) one may approximate
Near the Fermi energy ($E_
\t
ext{F}$) one may approximate
$
`
R_{i\ell}\^\sigma(r;E) \approx
$R_{i
\e
ll}
\^\s
igma(r;E)
\a
pprox
R_{i\ell}\^\sigma(r;E_\text{F})$
`
.
R_{i
\e
ll}
\^\s
igma(r;E_
\t
ext{F})$.
## Susceptibility
## Susceptibility
...
@@ -51,9 +51,9 @@ The transverse magnetic Kohn-Sham susceptibility is given by
...
@@ -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) \, .
& & \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
Here, $
\c
hi
\^
{
\u
parrow
\d
ownarrow}$ and
$
`
\chi\^{\downarrow\uparrow}$
`
correspond to $
`
\chi\^{+-}$
`
and
$
\c
hi
\^
{
\d
ownarrow
\u
parrow}$ correspond to $
\c
hi
\^
{+-}$ and
$
`
\chi\^{-+}$
`
, respectively.
$
\c
hi
\^
{-+}$, respectively.
### Dyson-like equation
### Dyson-like equation
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