I've heard a lot of music that is in a minor key but also has a flattened root note. I'm not sure if this is considered a flattened root, or a sharp 7th. For instance, in the key of Em, an E♭ (E flat) will be played which gives a dark sound. Or, if I was playing a chord progression in Em, I would play Em and then play Bmaj, which has that flat root.
Is there a specific mode this fits into?
Also, I've noticed this works with a sharp 6th. I'm not sure if this falls into the same mode as above, but for instance, I could play a chord progression in Em with these chords: Em, Bmaj, Gmaj, Amaj. Usually an Am would fit where the Amaj is, but instead the 6th of the key is sharp (or maybe a flat 7th?). Would this fit into the same mode as above, or is this something completely different?