Hi Jaganathan,
TCI is transmission configuration index which is used to find out the QCL types used. Which QCL-Type is applied is determined by TCI-RS-Set and DMRS. refer 38.214 - 5.1.5 for more information about TCI configuration,
As per specification if we increase sub carrier spacing then slot duration will be less. What is the relation between these two parameter, why lot duration is getting reduced?