Anomalous Hysteresis in Graphite/Boron Nitride Transistors DOI
Dacen Waters,

Derek Waleffe,

Ellis Thompson

et al.

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: May 16, 2025

Field-effect devices constructed from van der Waals (vdW) materials with hexagonal boron nitride (hBN) as gate dielectrics usually exhibit negligible hysteresis, enabling exquisitely detailed studies of diverse gate-voltage-tuned phenomena. Recently, a dramatic hysteresis effect, sometimes called the "gate doesn't work" or "electron ratchet" has been observed sporadically in otherwise typical vdW devices. Its lack reproducibility hindered clear identification its origin, which postulated to rely on combination bilayer graphene moiré patterns rotationally aligned hBN. Here, we report observing this effect thicker graphite channels, associating it single surface. Remarkably, persists at room temperature, without intentional hBN alignment, and even WSe2 monolayer inserted between Furthermore, exhibits continuous relaxation over long time scales. These observations impose strong constraints origin puzzling phenomenon, exciting potential applications if can be mastered.

Language: Английский

Magnetic Bloch states at integer flux quanta induced by super-moiré potential in graphene aligned with twisted boron nitride DOI Creative Commons
Yaqi Ma, Meizhen Huang, Xu Zhang

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 21, 2025

Two-dimensional electron systems in both magnetic fields and periodic potentials are described by the Hofstadter butterfly, a fundamental problem of solid-state physics. While moiré provide powerful method to realize this type spectrum, previous experiments have been limited fractional flux quanta regime, due difficulty building ~ 50 nm modulations. Here, we demonstrate super-moiré strategy overcome challenge. By aligning monolayer graphene (G) with 1.0° twisted hexagonal boron nitride (t-hBN), 63.2 bichromatic G/t-hBN is constructed, made possible exploiting electrostatic nature t-hBN potential. Under field $$B$$ , Bloch states at $$\phi /{\phi }_{0}=1-9$$ achieved observed as integer Brown-Zak oscillations, expanding from fractions integers. Theoretical analysis reproduces these experimental findings. This work opens promising avenues study unexplored explore emergent topological order engineer long-wavelength Twisted van der Waals structures shown many emerging physical properties, but uniform wavelengths usually < structural relaxation. authors report fabrication based on graphene/twisted nitride, showing homogeneous wavelength up resulting oscillations quanta.

Language: Английский

Citations

0
Sliding-driven symmetry breaking induced ferroelectric polarization and phonon property modulation in a β -GaSe bilayer DOI
Sihan Yan, Jia‐Han Zhang,

Bo Li

et al.

Applied Physics Letters, Journal Year: 2025, Volume and Issue: 126(11)

Published: March 1, 2025

Introducing ferroelectricity through symmetry breaking induces profound changes in the physical properties of a material. This study comprehensively tracks ferroelectric polarization and phonon property resulting from interlayer sliding β-GaSe bilayer. The results indicate that upper layer bilayer charge transfer, causing accompanied by periodic reversal non-polarized β-GaSe. Simultaneously, low-frequency optical phonons polarized structures soften significantly, exhibiting minimum or rapid decrease maximum value in-plane polarization. Additionally, has complex effects on transport, intriguing transport characteristics due to variations group velocity linewidth, which are closely related reveals not only achieved sliding-induced but also its changes, enriching our understanding associated condensed matter physics.

Language: Английский

Citations

0
Moiré Potential Independent of Moiré Size Down to a Few Nanometers in Sliding Ferroelectrics DOI
Jian Liao, Xinyu Lv, Takashi Taniguchi

et al.

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 14, 2025

Sliding ferroelectricity represents a way to realize atomically thin ferroelectric materials. Due the moiré pattern formed during stacking process, alternating domain network provides an attractive superlattice of electrostatic potential modulate electronic structures another material sitting on it. The relationship between magnitude and size, however, has been controversial in literature. In addition, how strong remains for sizes down 10 nm range is unclear. this study, we use contact-mode scanning tunneling microscopy with high spatial energy resolution show that independent size ranging from hundreds several nanometers. We also determined solely by specific materials used fabricate stack. This study important information sliding ferroelectrics can foster their application modulating other

Language: Английский

Citations

0
Strain‐Induced Moiré Polarization Vortices in Twisted‐Multilayer WSe2 DOI Creative Commons
Jeroen J. M. Sangers,

Abel Brokkelkamp,

Sònia Conesa-Boj

et al.

Small, Journal Year: 2025, Volume and Issue: unknown

Published: May 20, 2025

Abstract Moiré superlattices in 2D van der Waals (vdW) materials enable the engineering of local polarization textures and electrostatic potential landscapes. While vortices are demonstrated bilayer transition metal dichalcogenides (TMDs), their formation mechanisms multilayers remain unclear. Here, it is shown that multi‐twisted small‐angle multilayer WSe 2 , nanoscale strain fields, not twist alone, govern emergence, stability vortices. Using 4D scanning transmission electron microscopy (4D‐STEM) with an microscope pixel array detector (EMPAD), variations distributions spatially resolved nanometer precision. It found vortex‐like emerge exclusively regions significant strain, revealing a direct interplay between lattice reconstruction Moiré‐induced twisted multilayers. The findings establish as key tuning parameter for control, providing new pathways strain‐engineered vdW materials, chiral dipole textures, next‐generation low‐power electronic optoelectronic devices.

Language: Английский

Citations

0
Anomalous Hysteresis in Graphite/Boron Nitride Transistors DOI
Dacen Waters,

Derek Waleffe,

Ellis Thompson

et al.

Nano Letters, Journal Year: 2025, Volume and Issue: unknown

Published: May 16, 2025

Field-effect devices constructed from van der Waals (vdW) materials with hexagonal boron nitride (hBN) as gate dielectrics usually exhibit negligible hysteresis, enabling exquisitely detailed studies of diverse gate-voltage-tuned phenomena. Recently, a dramatic hysteresis effect, sometimes called the "gate doesn't work" or "electron ratchet" has been observed sporadically in otherwise typical vdW devices. Its lack reproducibility hindered clear identification its origin, which postulated to rely on combination bilayer graphene moiré patterns rotationally aligned hBN. Here, we report observing this effect thicker graphite channels, associating it single surface. Remarkably, persists at room temperature, without intentional hBN alignment, and even WSe2 monolayer inserted between Furthermore, exhibits continuous relaxation over long time scales. These observations impose strong constraints origin puzzling phenomenon, exciting potential applications if can be mastered.

Language: Английский

Citations

0