Motivated by the possibility of a strain tuning effect on electronic properties of graphene, the semimetal-Mott insulator transition process on the uniaxial honeycomb lattice is numerically studied using Determinant Quantum Monte Carlo. As our simulations are based on the half-filled repulsive Hubbard model, the system is sign problem free. Herein, the temperature-dependent DC conductivity is used to characterize electronic transport properties. The data suggest that metallic is suppressed in the presence of strain. More interestingly, within the finite-size scaling study, a novel antiferromagnetic phase arises at around $U\sim U_{c}$. Therefore, a phase diagram generated by the competition between interactions and strain is established, which may help to expand the application of strain effect on graphene.
We perform a systematic {\it ab initio} study of the work function and its uniform strain dependence for graphene and silicene for both tensile and compressive strains. The Poisson ratios associated with armchair and zigzag strains are also computed. Based on these results, we obtain the deformation potential, crucial for straintronics, as a function of the applied strain. Further, we propose a particular experimental setup with a special strain configuration that generates only the electric field, while the pseudomagnetic field is absent. Then, applying a real magnetic field, one should be ab…
Moiré systems have emerged in recent years as a rich platform to study strong correlations. Here, we will discuss a simple, experimentally feasible setup based on periodically strained graphene that reproduces several key aspects of twisted moiré heterostructures -- but without introducing a twist. We consider a monolayer graphene sheet subject to a $C_2$-breaking periodic strain-induced psuedomagnetic field (PMF) with period $L_M \gg a$, along with a scalar potential of the same period. This system has {\it almost ideal} flat bands with valley-resolved Chern number $\pm 1$, where the deviatio…
Transition metal oxides possess complex free energy surfaces with competing degrees of freedom. Photoexcitation allows shaping of such rich energy landscapes. In epitaxially strained $\mathrm{La_{0.67}Ca_{0.33}MnO_3}$, optical excitation with a sub-100 fs pulse above $2\ \mathrm{mJ/cm^2}$ leads to a persistent metallic phase below 100 K. Using single-shot optical and terahertz spectroscopy, we show that this phase transition is a multi-step process. We conclude that the phase transition is driven by partial charge order melting, followed by growth of the persistent metallic phase on longer tim…
Landau levels in curved space realized in strained graphene
Rudolf Peierls Centre for Theoretical Physics（鲁道夫·皮尔斯理论物理中心）；Donostia International Physics Center（圣塞巴斯蒂安国际物理中心）；IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）；Brown Theoretical Physics Center and Department of Physics, Brown University（布朗大学布朗理论物理中心及物理系）
We analyze the effects of the long-range Coulomb interaction on the distribution of Berry curvature among the bands near charge neutrality of twisted bilayer graphene (TBG) closely aligned with hexagonal boron nitride (hBN). Due to the suppressed dispersion of the narrow bands, the band structure is strongly renormalized by electron-electron interactions, and thus, the associated topological properties of the bands are sensitive to filling. Using a Hartree formalism, we calculate the linear and nonlinear Hall conductivities, and find that for certain fillings, the remote bands contribute subst…
Three symmetries prevent a twisted bilayer of graphene from developing an in-plane spontaneous magnetization in the absence of a magnetic field - time reversal symmetry, $C_2$ symmetry to $π$ rotation and $C_3$ symmetry to $2π/3$ rotation. In contrast, there are experimental and theoretical indications that, at certain electron densities, time reversal and $C_2$ symmetries are broken spontaneously, while the $C_3$ symmetry is often broken due to strain. We show that in-plane orbital magnetization is a very sensitive probe to the simultaneous breaking of these three symmetries, exhibiting surpr…
Modification of interatomic distances due to high pressure leads to exotic phenomena, including metallicity, superconductivity and magnetism, observed in materials not showing such properties in normal conditions. In two-dimensional crystals, such as graphene, atomic bond lengths can be modified by more that 10 percent by applying in-plane strain, i.e., without generating high pressure in the bulk. In this work, we study the strain-induced Mott transition on a honeycomb lattice by using computationally inexpensive techniques, including Gutzwiller Wave Function (GWF) and different variants of G…
