From: https://en.wikipedia.org/wiki/Black_Sun_(symbol)#Wewelsburg_mosaic_and_the_Nazi_period

Neo-Nazism[edit]

A leather belt with the black sun symbol as belt buckle. The item is from the 2010s.

In the late 20th century, the Black Sun symbol became widely used by neo-fascist, neo-Nazi,^[8] the far-right and white nationalists. The symbol often appears on extremist flags, t-shirts, posters, websites and in extremist publications associated with such groups. Modern far-right groups often refer to the symbol as the sun wheel or Sonnenrad.^[6][9][10]

The name "Black Sun" came into wider use after the publication of a 1991 occult thriller novel, Die Schwarze Sonne von Tashi Lhunpo (The Black Sun of Tashi Lhunpo), by the pseudonymous author Russell McCloud. The book links the Wewelsburg mosaic with the neo-Nazi concept of the "Black Sun", invented by former SS officer Wilhelm Landig as a substitute for the Nazi swastika and a symbol for a mystic energy source that was supposed to renew the Aryan race.^[3][4][11]

….

Along with other symbols from the Nazi era such as the Wolfsangel, the Sig Armanen rune, and the Totenkopf, the black sun is employed by some neo-Nazi adherents of Satanism.^[13] Scholar Chris Mathews writes:

The Black Sun motif is even less ambiguous. Though based on medieval German symbols, the Wewelsburg mosaic is a unique design commissioned specifically for Himmler, and its primary contemporary association is Nazi occultism, for which Nazi Satanic groups and esoteric neo-Nazis adopt it.^[13]

The Ukrainian Azov Regiment, founded in 2014, used the symbol as part of its logo.^[14][15]