Proximity Ferroelectricity in Compositionally Graded Structures

Journal Article · Thu Feb 19 00:00:00 UTC 2026 · Advanced Electronic Materials

DOI: https://doi.org/10.1002/aelm.202500661 · OSTI ID:3029590

Eliseev, Eugene A.  ^[1]; Morozovska, Anna N.  ^[1]; Kalinin, Sergei V. ^[2]; Chen, Long‐Qing  ^[3]; Gopalan, Venkatraman  ^[3]

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1. National Academy of Sciences of Ukraine (NASU), Kyiv (Ukraine)
2. Univ. of Tennessee, Knoxville, TN (United States)
3. Pennsylvania State Univ., University Park, PA (United States)

Proximity ferroelectricity is a novel paradigm for inducing ferroelectricity in a non-ferroelectric polar material, such as AlN or ZnO that are typically unswitchable with an external field below their dielectric breakdown field. When placed in direct contact with a thin switchable ferroelectric layer (such as Al_1-xSc_xN or Zn_1-xMg_xO), they become a practically switchable ferroelectric. Using the thermodynamic Landau-Ginzburg-Devonshire theory, in this work, we perform the finite element modeling of the polarization switching in the compositionally graded AlN-Al_1-xSc_xN, ZnO-Zn_1-xMg_xO, and MgO-Zn_1-xMg_xO structures sandwiched in both a parallel-plate capacitor geometry as well as in a sharp probe-planar electrode geometry. We reveal that the compositionally graded structure allows the simultaneous switching of spontaneous polarization in the whole system by a coercive field significantly lower than the electric breakdown field of unswitchable polar materials. The physical mechanism is the depolarization electric field determined by the gradient of chemical composition “x”. The field lowers the steepness of the switching barrier in the otherwise unswitchable parts of the compositionally graded AlN-Al_1-xSc_xN and ZnO-Zn_1-xMg_xO structures. In the MgO-like regions of the compositionally graded MgO-Zn_1-xMg_xO structure, a shallow double-well free energy potential emerges. Proximity ferroelectric switching of the compositionally graded structures placed in the probe-electrode geometry occurs due to nanodomain formation under the tip. We predict that a gradient of chemical composition “x” significantly lowers effective coercive fields of the compositionally graded AlN-Al_1-xSc_xN and ZnO-Zn_1-xMg_xO structures compared to the coercive fields of the corresponding multilayers with a uniform chemical composition in each layer. A tip-induced switching further lowers the coercive field, enabling control of ferroelectric domains in otherwise unswitchable compositionally graded structures, which can provide nanoscale domain control for memory, actuation, sensing, and optical applications.

• Research Organization: Energy Frontier Research Centers (EFRC) (United States). Center for 3D Ferroelectric Microelectronics Manufacturing (3DFeM2); Pennsylvania State Univ., University Park, PA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0020145; SC0021118
• OSTI ID: 3029590
• Journal Information: Advanced Electronic Materials, Journal Name: Advanced Electronic Materials Journal Issue: 7 Vol. 12; ISSN 2199-160X
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English