相关论文: Detecting symmetry breaking in magic angle graphen…
The low-energy excitations of graphene are relativistic massless Dirac fermions with opposite chiralities at valleys K and K'. Breaking the chiral symmetry could lead to gap opening in analogy to dynamical mass generation in particle…
Symmetry breaking governs most fascinating phenomena in crystals, such as ferroelectricity, nonlinear optics, piezoelectricity, ferromagnetism, and superconductivity. In two-dimensional materials, a wide variety of tuning knobs presents…
Strongly interacting electrons in solid-state systems often display tendency towards multiple broken symmetries in the ground state. The complex interplay between different order parameters can give rise to a rich phase diagram. Here, we…
Using first-principles calculations of graphene having high-symmetry distortion or defects, we investigate band gap opening by chiral symmetry breaking, or intervalley mixing, in graphene and show an intuitive picture of understanding the…
The understanding of quantum many-body states in twisted bilayer graphene at the magic angle has been greatly improved both in experiment and in theory. However, away from the exactly solvable chiral limit and the sign-problem-free charge…
We revisit the global phase diagram of magic-angle twisted bilayer and [symmetric] trilayer graphene (MA-TBG/TSTG) in light of recent scanning tunneling microscopy (STM) measurements on these materials. These experiments both confirmed the…
We study the phase diagram of magic-angle twisted symmetric trilayer graphene in the presence of uniaxial heterostrain and interlayer displacement field. For experimentally reasonable strain, our mean-field analysis finds robust Kekul\'e…
The discovery of correlated electronic phases, including Mott-like insulators and superconductivity, in twisted bilayer graphene (TBLG) near the magic angle, and the intriguing similarity of their phenomenology to that of the…
Measuring degeneracy and broken-symmetry states of a system at nanoscale requires extremely high energy and spatial resolution, which has so far eluded direct observation. Here, we realize measurement of the degeneracy and subtle…
The discovery of alternating superconducting and insulating ground-states in magic angle graphene has suggested an intriguing analogy with cuprate high-$T_c$ materials. Here we argue that the network states of small angle twisted bilayer…
Two-dimensional quantum materials offer a robust platform for investigating the emergence of symmetry-broken ordered phases owing to the high tuneability of their electronic properties. For instance, the ability to create new electronic…
The unique sensitivity of optical response to different types of symmetry breaking can be used to detect and identify spontaneously ordered many-body states in bilayer graphene. We predict a strong response at optical frequencies, sensitive…
Spontaneous symmetry breaking provides a powerful window into the nature of underlying electronic orders. In strongly correlated systems, multiple symmetry-breaking orders can arise simultaneously. and their interplay generates an intricate…
Correlated insulators are frequently observed in magic angle twisted bilayer graphene at even fillings of electrons or holes per moir\'e unit-cell. Whereas theory predicts these insulators to be intervalley coherent excitonic phases, the…
The interaction between electrons in graphene under high magnetic fields drives the formation of a rich set of quantum Hall ferromagnetic phases (QHFM), with broken spin or valley symmetry. Visualizing atomic scale electronic wavefunctions…
Motivated by recent low-temperature magnetoresistance measurements in twisted bilayer graphene aligned with hexagonal Boron Nitride substrate, we perform a systematic study of possible symmetry breaking orders in this device at a filling of…
Twisted bilayer graphene exhibits isolated, relatively flat electronic bands near charge neutrality when the interlayer rotation is tuned to specific magic angles. These small misalignments, typically below 1.1{\deg}, result in long-period…
In this work, we determine states of electronic order of small-angle twisted bilayer graphene. Ground states are determined for weak and strong couplings which are representatives for varying distances of the twist-angle from its magic…
The nature of the pseudogap state is widely believed as a key to understanding the pairing mechanism underlying unconventional superconductivity. Over the past two decades, significant efforts have been devoted to searching for spontaneous…
We show how the pairing symmetry of superconducting states in twisted bilayer graphene can be experimentally identified by theoretically studying effects of externally applied in-plane magnetic field and strain. In the low field regime,…