How to Make ggsave Use TikZ Graphics Device

I have the following ggplot2 R code chunk:

`````````{r, dev = "tikz"}
my_graph <- ggplot(iris, aes(x = Petal.Length, y = Sepal.Length, color = Species)) +
xlab("Petal length (cm)") + ylab("Sepal length") +
ggtitle("Petal length vs. sepal length") +
geom_point() + theme_bw()
my_graph
```
``````

By adding the chunk option `dev = "tikz"`, I was able to make the plot use the same font as my LaTeX font (which is Latin Modern by default). I can save the plot to a separate PDF:

``````ggsave(my_graph, filename = "petal-length-vs-sepal-length.pdf")
``````

But the problem is that the output used a different font than the one I want. I want it to use my document font, Latin Modern. Computer Modern is also fine. I tried adding the argument `device = "tikz"`, but that is an unknown TikZ device. According to the ggplot2 documentation, the device `tikz` is not supported by the `ggsave()` function. My next option is to set the font in the theme:

``````my_graph <- ggplot(iris, aes(x = Petal.Length, y = Sepal.Length, color = Species)) +
xlab("Petal length (cm)") + ylab("Sepal length") +
ggtitle("Petal length vs. sepal length") +
geom_point() + theme_bw(base_family = "Latin Modern")
``````

But the Latin Modern or the Computer Modern fonts are not available. I can find the available fonts by running `names(pdfFonts())`:

`````` [1] "serif"                "sans"                 "mono"
[4] "AvantGarde"           "Bookman"              "Courier"
[7] "Helvetica"            "Helvetica-Narrow"     "NewCenturySchoolbook"
[10] "Palatino"             "Times"                "URWGothic"
[13] "URWBookman"           "NimbusMon"            "NimbusSan"
[16] "URWHelvetica"         "NimbusSanCond"        "CenturySch"
[19] "URWPalladio"          "NimbusRom"            "URWTimes"
[22] "ArialMT"              "Japan1"               "Japan1HeiMin"
[25] "Japan1GothicBBB"      "Japan1Ryumin"         "Korea1"
[28] "Korea1deb"            "CNS1"                 "GB1"
``````