Unveiling the double-well energy landscape in a ferroelectric layer

Modeling of Negative Capacitance in Ferroelectric Thin Films

“…Since a barrier height of the double well potential in the model extracted from the fitting result is in agreement with the known value of the height for the strained epitaxial BaTiO 3 thin film, it seems reasonable that the homogeneous switching occurs during the application of the short pulse. Recently, Hoffmann et al reported that they experimentally identified a double well barrier of polycrystalline Hf 0.5 Zr 0.5 O 2 ferroelectric thin film by adopting the similar pulse measurement . However, their pulse experiment resulted in the Landau energy barrier as small as 0.65 meV f.u.…”

“…This meant that the static NC effect of the BaTiO 3 film disappeared. Therefore, suppression of the permanent ferroelectric switching is one of the very fundamental assets for the emergence of the NC effect from the ferroelectric or dielectric/ferroelectric thin films . All the following numerical simulations and analytical analysis, therefore, assumed no such charge exchange or injection, which could be a feasible assumption for practical applications considering the short‐pulse type operation of the relevant devices (<100 ns).…”

Van der Waals Contact to 2D Semiconductors with a Switchable Electric Dipole: Achieving Both n‐ and p‐Type Ohmic Contacts to Metals with a Wide Range of Work Functions

“…Here, for the MpSJ with the same metal and the same semiconductor material, both n‐type and p‐type SB‐free contact can be achieved by switching the built‐in electric dipole of the semiconductor. It is interesting to note that, for 2D ferroelectrics (e.g., group III 2 ‐VI 3 ferroelectrics), the dipole switching can be realized by using an external electric field 59,60. Our scheme here to obtain both contact‐types in 2D pS is very different to that in Si CMOS, in which n‐type (e.g., boron) and p‐type (e.g., arsenic) substitutional doping are used to change the contact type.…”

A century of ferroelectricity

“…The double-well potential, the key to ferroelectric behaviour, was also recently observed using Hf 0.5 Zr 0.5 O 2 (ref. 8 ). This material shows no ferroelectricity in its bulk form, yet becomes a ferroelectric when it is in the form of a ferroelectric thin film 9 , indicating the role that improved growth methods can play.…”