Effect of electric field on the hysteresis and switching behavior of the MoS$_2$/Au(111) heterojunction

It can be said that the interface is the device. A holistic understanding of interfacial interactions and electronic structureof 2D materials with electrodes is far from complete, but is necessary for tailored electronic devices, including in mem-ristors for neuromorphic computing. Here, we develop a computational protocol to study the hysteretic behavior andcharge carrier transport mechanisms of the MoS2/Au(111) junction under applied electric fields using first-principlescalculations. We show that even in the absence of defects, formation of conducting bridges or significant atomic recon-struction, the pristine MoS2/Au(111) junction shows hysteresis in the induced polarization, the electron barrier heights,and the carrier transport. A primary finding from our calculations is the modulation of the Schottky barrier and electrontunneling barrier as a mechanism behind the resistive switching mechanism of the pristine MoS2/Au(111) junction. Wealso show that changes of interfacial dipole moments with external electric field contributes to the memory effect bylowering the electron barriers. Our results indicate that in the absence of defects, electric-field induced relaxation ofthe interlayer spacing and clustering of Mo-atoms provides the means for spontaneous polarization. Based on this un-derstanding of the MoS2/Au(111) junction, we propose that a back-to-back double Schottky barrier ferroelectric tunneljunction (FTJ) diode can be used to model the characteristics of MoS2/Au(111) heterojunction. Our study has implica-tions for revealing the physical origins of the onset of hysteretic properties of heterostructures based on low-dimensionalmaterials, providing a more complete understanding of the mechanisms in resistive switching.