Can we put a yield sign to warn drivers to yield when turning left at a sharp intersection?
No, it is not allowed to mix stop and yield signs in a single intersection with exceptions for large multi-lane intersections and channelized turn lanes.
Text from MUTCD:
Section 2B.04: Right-of-Way at Intersections
Standard
Except as provided in Section 2B.09, STOP signs and YIELD signs shall not be installed on different approaches to the same unsignalized intersection if those approaches conflict with or oppose each other.
Resources
January 2014