B767 Captain reported receiving 'Gear Doors' and 'Gear Disagree' master cautions upon raising the gear during takeoff. After troubleshooting; the messages would not dissipate; so the crew elected to return to the departure airport.

Narrative

Immediately after taking off from Runway XXL at ZZZ and upon raising the gear we received a master caution with a 'Gear Doors' and 'Gear Disagree' EICAS with the associated amber Doors and Gear annunciator lights. After leveling at a safe altitude; 4;000 feet AGL; and at a safe airspeed; 230 KIAS; we lowered the gear in accordance with QRH. After receiving 3 green down and locked indications and with no illuminated EICAS or annunciator lights we decided to re-raise the gear to determine if we had just had a momentary slightly gaping gear door and/or proximity switch that may have not quite been made. Unfortunately; we received the same indications again so at this point that I gave the aircraft and comms to the FO so that I could communicate with Dispatch and Maintenance Control. After an in-depth discussion with Maintenance Control and with their agreement it was determined that we more than likely had a bad proximity switch and/or a gaping gear door and that the best course of action would be to return to ZZZ to have it inspected by maintenance. It was decided that an emergency did not need to be declared because at that point we had already been able to normally lower the gear and with absolutely no other secondary indications of anything out of the ordinary we had no reason to believe that we were going to have anything but a normal approach and landing.After lowering the gear; again normally; and again with absolutely no abnormal indications we made a normal approach and landing at ZZZ. During what seemed to be a normal rollout; ATC Tower personnel reported seeing sparks emanating from what appeared to be the left main gear area. After safely clearing the runway and stopping the aircraft we asked to have the firefighting personnel dispatched to our location for an inspection. After a lengthy inspection it was determined that there had been some damage in the left main gear break area (broken 'break linkage bar') and that we would need to eventually be towed in. Upon returning to the gate; I debriefed with Dispatch and Flight Operations via phone. We were also able to go outside to meet with maintenance personnel who at that time were able to show us parts that had been recovered from our takeoff after a subsequent runway inspection.