Not jazz (more like jazzish-R&B), but as I was listening to this song, I heard some harmonic scales in his ad lib. At 4:06, you hear a minor arpeggio. At 4:12, you can hear the harmonic minor scale as he comes down in thirds. When I hear about the harmonic minor, my mind immediately jumps to music from Aladdin – Egyptian/Arabic music. But this goes to show that even in R&B, you can still use the harmonic scale.