PhD Mid-term Seminar Series: Ferroelectric hysteresis in single layer Graphene/hBN moiré superlattice

CIC nanoGUNE Seminars

Speaker

Quang Bao Tu
CIC nanoGUNE

When

2025/03/03
11:00

Place

CIC nanoGUNE Seminar room, Tolosa Hiribidea 76, Donostia-San Sebastian

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Ferroelectric materials have the unique ability to maintain and reverse electric polarization with an external applied electric field, making them valuable for applications such as non-volatile random-access memory, transducers, actuators and electro-optic modulators.[1] Traditionally, this property was thought to be exclusive to insulating materials, as insulators are crucial for sustaining polarization and enabling field-induced switching. However, recent research on two-dimensional (2D) material has shown that ferroelectric properties can also exist in semiconductors and metals.[2] Recently, emergent unconventional ferroelectricity has been demonstrated in the moiré superlattices of bilayer graphene and hexagonal boron nitride (hBN), hosting non-centrosymmetric stacking order [3,4]. Whether such phenomenon can persist in non-centrosymmetric single layer graphene (SLG)-hBN moiré superlattices has still remained elusive. In this talk, we demonstrate a ferroelectric response in SLG-hBN moiré superlattice. This hysteretic behavior persists from 2K to room temperature, offering further opportunities for high-mobility, ultrathin non-volatile devices. 

References: 

C. Wang et al., Nat. Mater. 22, 542 (2023). 

S. Bhowal and N. A. Spaldin, Annu. Rev. Mater. Res. 53, 53 (2023). 

Z. Zheng et al., Nature 588, 71 (2020). 

4. X. Yan et al., Nature 624, 551 (2023).