Nope, you can’t do that by default, the only choices are those visible in the category setting Topic List Sort By:
- Activity
- Category
- Created
- Likes
- Original Post Likes
- Posters
- Posts
- Views
- Votes
To get a list sorted alphabetically I think your only choice is to build a plugin. Or follow the workarounds you can find in Feature request: Sort display of topics Alphabetically