...A B C D D# E F G# A
Just the list of tones isn't enough to describe in a meaningful way what is happening. It could have various musical meanings.
D# could be a chromatic passing or neighbor tone.
D# could be the temporary leading tone of
A lot depends on the harmonic context. Even if you have playing only a single melodic line there is usually an implied harmonic context. The harmonic context will really be the thing that informs us about what it could be called.
E F E D# E ...isn't really enough to say.
D# looks like a chromatic neighbor tone, but whatever you played before it could imply something else.
...use of the tritone with a minor scale
That wording sort of implies a harmonic tritone. If you aren't playing
D# simultaneously or outlining
D# in some way, that wording might be a bit misleading. At least for me I would be expecting to hear the discordant sound of a tritone. Just
E F E D# E alone won't necessarily produce that tritone sound.
An additional point occurred to me that I think is worth mentioning. Whether this tone is a raised
^4 or lowered
^5 scale degree it is an alteration of a tonal degree. (The tonal degrees are tonic
^4, and dominant
^5.) Glossing over some details, tonal music basically does not alter those degree, or those alterations signal a shift in tonal center. That can be contrasted with alterations to modal degrees like the submediant where such alterations don't change the tonal center but change the mode. For example, in minor a raised submediant gives the modal flavor of the Dorian mode.
In terms of what to call this particular tone we can first ask if a tonal shift if occurring. If not, then some sort of unessential, embellishment is the likely best description. I don't think that changes anything about my answer above, but it might help to point out the tonal degree alteration aspect.
There is one other possibility. This may be stretch, but given that the OP mentioned in comments...
The harmonic context was basically a constant alternation between the tonic minor (Am) and the dominant major (E). Just a simple improvisation
...an additional thing should be pointed out.
Let's take the list of tones and permute them to start on
[E F G# A] [B C (D) E]
- the square brackets denote tetrachords
- the parenthesis on
D natural mean either omit or treat an unessential
- the arrow shows the addition of
D# to the scale
If we treat the scale this way, we get two harmonic tetrachords and the scale becomes
E double harmonic. If you play this scale on
A, you would call it the fourth mode of the double harmonic scale. According to Wikipedia the fourth mode is the most common mode of the scale.
Strictly speaking the
D natural should be skipped in order to really define the double harmonic. In which case we are dealing with an altered tonal degree.