G200 Captain reported limited aileron controllability during climbout. Flight crew returned to departure airport and landed safely.

Narrative

Second leg of the day; ZZZ-ZZZ1. Quick turn/pre-flight checks were completed; including a full flight control check; no anomalies noted. Takeoff clearance was received for Runway XXL; 090 heading climb to 2000 feet. Takeoff roll and initial climbout were uneventful. Autopilot was engaged around 1500 feet. We were handed off to departure control and given a climb to 7000 feet and a left turn to the northwest. Within a few seconds of initiating the autopilot to make the left turn I noticed an amber A on the Primary Flight Display; indicating what I recall is a mis-trim situation whereas the autopilot is experiencing difficulty moving the ailerons. A few seconds later the amber indication changed to red. At this point I asked the Pilot Flying (PF) to turn off the autopilot and hand fly the airplane. Once the autopilot was disconnected it became apparent that movement of the yoke in the roll axis was very difficult. Initially; with enough force; the roll control would 'unbind' but then would quickly become difficult to move again. At this point; on what could be considered a high downwind; we called ATC and asked to return to ZZZ. The airplane was able to be rolled ever so slightly with heavy inputs; but normal aileron control was not possible. Rudder and differential thrust were utilized to help turn the aircraft back towards the airport. A short discussion was had after reading the 'jammed aileron' checklist. The crew decided that; given the low altitude and close proximity to the runway; it was best to not introduce a new factor into an still unknown failure. We were cleared for the GPS approach to Runway XXL and landed without incident. Post flight maintenance inspection seemed to point towards a partially seized aileron servo actuator in the left wing. Hindsight being 20/20; if we would have performed the jammed aileron procedure; it likely would have given us more authority in the right aileron but only from the copilot/Pilot Monitoring position; but since positive directional control of the airplane was maintained throughout we believe proper decision making prevailed