Which god was the sun disk worshipped by Akhenaten? Aten was that god.
Aten was the visible sun disk that became the focus of the religious system established by the Egyptian pharaoh Akhenaten. Earlier Egyptians used “aten” to mean a disk or orb of the sun, and the deity was initially connected with traditional solar gods such as Ra. Under Akhenaten, however, Aten was elevated into the supreme—and officially sole—god of the state cult.
Aten's distinctive image was not an animal-headed or human-shaped figure. Instead, artists showed a radiant disk whose rays ended in human hands, sometimes extending the ankh, the sign of life, toward Akhenaten and Queen Nefertiti. The Great Hymn to the Aten presents the disk as creator and giver of life.
Akhenaten founded the new capital Akhetaten, modern Amarna, for the cult. Atenism did not last long after his death: traditional temples reopened, Amun regained prominence, and later rulers dismantled or suppressed many Amarna monuments. Aten is therefore different from Ra, the older and more enduring traditional sun god.