High tunneling electroresistance in ferroelectric tunnel junctions based on two-dimensional -In₂Se₃/MoTe₂ van der Waals heterostructures

Ferroelectric polarization-controlled band alignment can be realized in van der Waals heterostructures (vdWHs), which can be used to create new types of ferroelectric tunnel junctions (FTJs). In this work, we design six probable configurations of two-dimensional vdWHs based on a two-dimensional alpha-In2Se3 ferroelectric material which has two opposite polarization states P up arrow and P down arrow, and the semiconductor MoTe2. First-principles calculations show robust ferroelectric polarization-controlled switching behavior between the high conductance state in configuration AA-P down arrow and the low conductance state in configuration AA-P up arrow in the most stable AA stacked vdWHs. Based on this vdWH, a two-dimensional transverse FTJ with AA-P down arrow or AA-P up arrow as the tunneling barrier and (In0.5Sn0.5)(2)Se-3 monolayers (n-type doped) as electrodes is designed. The tunneling electroresistance ratio of the FTJs at the Fermi level reaches 1.22 x 10(4)% when the tunneling barrier contains two repeating units N = 2 and can be greatly increased by increasing the thickness of the ferroelectric layer. Analysis of the work function, charge redistribution, and local density of states is performed to interpret the above phenomena. The findings suggest the great potential of the AA stacked alpha-In2Se3/MoTe2 vdWH in the design of high-performance FTJs and application in high-density non-volatile memory devices.