Article
Physics, Multidisciplinary
Tawfiqur Rakib, Pascal Pochet, Elif Ertekin, Harley T. Johnson
Summary: The study reveals that the partially filled band and symmetry breaking phenomena in magic-angle twisted bilayer graphene can be explained by the large out-of-plane displacement induced by the interlayer twist. This observation provides insights into the exotic electronic properties in magic-angle twisted bilayer graphene and may offer a strategy to mitigate the effects of disorder.
COMMUNICATIONS PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Aitor Garcia-Ruiz, Hai-Yao Deng, Vladimir V. Enaldiev, Vladimir Fal'ko
Summary: The study employs a hybrid k . p-theory-tight-binding model to describe interlayer coupling in both Bernal and twisted graphene structures, finding that additional terms introduce electron-hole asymmetry in the band structure of twisted bilayers. In twistronic multilayer graphene, these terms produce only a subtle change in moire miniband spectra, confirming the broad applicability of the Bistritzer-MacDonald model for twisted interface coupling in such systems.
Article
Materials Science, Multidisciplinary
Philipp Rosenzweig, Hrag Karakachian, Dmitry Marchenko, Ulrich Starke
Summary: Recently, the graphene-SiC interface has been used to epitaxially grow stable, monoelemental, two-dimensional (2D) layers via intercalation. These 2D layers, in combination with graphene, form a new class of quantum materials with different properties compared to their bulk crystals. This study demonstrates the successful modification of band alignment between graphene and silver through surface charge-transfer doping, leading to enhanced metallization of the heterostructure.
Article
Physics, Applied
Julian Gil-Pinzon, Nalat Sornkhampan, Amber Woods, Yuriy Vlasov, Grover Larkins
Summary: Possible superconductivity was observed in phosphorus-doped graphene, with resistivity and susceptibility measurements used as main indicators. Magnetic-induced phenomena in phosphorus-doped multilayer graphene resemble effects seen in type II multilayer superconductors, such as Nernst peaks and well-defined hysteresis curves.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
Nalat Sornkhampan, Julian Gil-Pinzon, Justin Ponce-Zuniga, Amber Woods, Yuriy Vlasov, Grover Larkins
Summary: Phenomena consistent with mixed-state superconductivity have been observed in phosphorus-doped graphene films at temperatures as high as 260K. Evidence of vortices and flux flow in the mixed state was presented through well-defined Nernst peaks.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2021)
Editorial Material
Chemistry, Physical
Matthew Yankowitz
Summary: A new spectroscopic technique exploits overlapping electronic bands to investigate the highly correlated states of magic-angle twisted trilayer graphene.
Article
Materials Science, Multidisciplinary
Chunlong Wu, Qiang Wan, Cao Peng, Shangkun Mo, Renzhe Li, Keming Zhao, Yanping Guo, Da Huo, Chendong Zhang, Nan Xu
Summary: The study reports evidence of a high-order moire effect and multiple Dirac cone replicas on a graphene-SiC heterostructure. Despite a weak first-order moire effect due to large lattice mismatch and rotation angle, a high-order moire effect with a 1.9 nm periodicity is experimentally observed, along with Dirac cone replicas with momentum transfer by second- and third-order reciprocal lattice vectors. This demonstrates the potential to engineer moire systems without the limitation of small lattice constant mismatches.
Article
Physics, Multidisciplinary
Klaus Zollner, Jaroslav Fabian
Summary: This study investigates the twist-angle and gate dependence of the proximity exchange coupling in twisted graphene on monolayer Cr2Ge2Te6 from first principles. The results show that the twist angle has a significant impact on the exchange coupling of graphene, which can be further controlled by a transverse electric field and the interlayer distance.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Simon Turkel, Joshua Swann, Ziyan Zhu, Maine Christos, K. Watanabe, T. Taniguchi, Subir Sachdev, Mathias S. Scheurer, Efthimios Kaxiras, Cory R. Dean, Abhay N. Pasupathy
Summary: The magic-angle twisted trilayer graphene has shown a potential for engineering strongly correlated flat bands. Using low-temperature scanning tunneling microscopy, researchers have observed a strong reconstruction of the moire lattice in real trilayer samples, leading to the formation of localized twist-angle faults. These localized regions exhibit different electronic structures compared to the background regions, resulting in a doping-dependent, spatially granular electronic landscape.
Article
Materials Science, Multidisciplinary
Alexander A. Zyuzin, A. Yu Zyuzin
Summary: We study the conditions for the emergence of preformed Cooper pairs in materials with flat bands. Using a semimetal as an example, we focus on the s-wave intervalley pairing channel. The nearly dispersionless flat band promotes local Cooper pair formation, allowing the system to be modeled as an array of superconducting grains. Dispersion between the grains leads to global phase-coherent superconductivity at low temperatures.
Article
Multidisciplinary Sciences
Peter Rickhaus, Folkert K. de Vries, Jihang Zhu, Elias Portoles, Giulia Zheng, Michele Masseroni, Annika Kurzmann, Takashi Taniguchi, Kenji Watanabe, Allan H. MacDonald, Thomas Ihn, Klaus Ensslin
Summary: This study discovered a correlated electron-hole state in double-bilayer graphene twisted to 2.37 degrees, where moire states retain much of their isolated bilayer character. This allows the generation of an energetic overlap between narrow isolated electron and hole bands with good nesting properties, leading to the formation of ordered states with reconstructed Fermi surfaces consistent with a density-wave state that can be tuned without introducing chemical dopants.
Review
Physics, Applied
Pierre A. Pantaleon, Alejandro Jimeno-Pozo, Hector Sainz-Cruz, Phong Vo Tien, Tommaso Cea, Francisco Guinea
Summary: This Perspective article summarizes the study of superconductivity and correlated phases in non-twisted graphene bilayers and trilayers. The authors provide an overview of the recent experimental findings and analyze the theoretical models that aim to explain them. Superconductivity and cascades of correlated phases have been discovered in Bernal bilayer and rhombohedral trilayer graphene.
NATURE REVIEWS PHYSICS
(2023)
Article
Physics, Multidisciplinary
Jung Pyo Hong, Tomohiro Soejima, Michael P. Zaletel
Summary: Experimental works have shown that magic angle twisted bilayer graphene exhibits spontaneous symmetry-breaking transitions, and scientists have identified competitive symmetry-breaking states by analyzing sublattice polarization and Kekule distortions in scanning tunneling microscopy.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Peter Cha, Aavishkar A. Patel, Eun-Ah Kim
Summary: The understanding of correlated insulating states in magic-angle twisted bilayer graphene involves various kinds of spontaneous symmetry breaking, while the effects of fluctuations of order parameters at integer fillings on charge transport are investigated. The competition between short-distance ferromagnetic interactions and frustrating extended-range antiferromagnetic interactions leads to the formation of stripy mesoscale domains above the ordering transition.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Zhongwei Dai, Zhaoli Gao, Sergey S. Pershoguba, Nikhil Tiwale, Ashwanth Subramanian, Qicheng Zhang, Calley Eads, Samuel A. Tenney, Richard M. Osgood, Chang-Yong Nam, Jiadong Zang, A. T. Charlie Johnson, Jerzy T. Sadowski
Summary: The study presents experimental evidence of electronic and optical interlayer resonances in graphene van der Waals heterostructure interfaces. Using spectroscopic mode of a low-energy electron microscope (LEEM) and Raman spectroscopy, researchers found an increase in the interlayer spacing of 30 degrees twisted bilayer graphene and observed a unique type of Fano resonance around the D and G modes of the graphene lattice vibrations. This robust Fano resonance is a direct result of quantum confinement and the interplay between discrete phonon states and the excitonic continuum.
PHYSICAL REVIEW LETTERS
(2021)
