A Si/Ge heterojunction line tunnel field-effect transistor(LTFET) with a symmetric heteromaterial gate is proposed.Compared to single-material-gate LTFETs, the heteromaterial gate LTFET shows an off-state leakage current that is three orders of magnitude lower, and steeper subthreshold characteristics, without degradation in the on-state current. We reveal that these improvements are due to the induced local potential barrier, which arises from the energy-band profile modulation effect. Based on this novel structure, the impacts of the physical parameters of the gap region between the pocket and the drain, including the work-function mismatch between the pocket gate and the gap gate, the type of dopant, and the doping concentration, on the device performance are investigated. Simulation and theoretical calculation results indicate that the gap gate material and n-type doping level in the gap region should be optimized simultaneously to make this region fully depleted for further suppression of the off-state leakage current. A Si / Ge heterojunction line tunnel field-effect transistor (LTFET) with a symmetric heteromaterial gate is proposed. Compared to single-material-gate LTFETs, the heteromaterial gate LTFET shows an off-state leakage current that is three orders of magnitude lower, and steeper subthreshold characteristics, without degradation in the on-state current. We reveal that these improvements are due to the induced local potential barrier, which arises from the energy-band profile modulation effect. Based on this novel structure, the impacts of the physical parameters of the gap region between the pocket and the drain, including the work-function mismatch between the pocket gate and the gap gate, the type of dopant, and the doping concentration, on the device performance are investigated. that the gap gate material and n-type doping level in the gap region should be optimized simultaneously to make this region fully depleted for further suppre ssion of the off-state leakage current.