We demonstrate the anomalous Hall effect (AHE) in single-layer graphene exchange coupled to an atomically flat yttrium iron garnet (YIG) ferromagnetic thin film. The conductance has magnitude of ∼0.09(2e2/h) at low temperatures and is measurable up ∼300 K. Our observations indicate not only proximity-induced ferromagnetism graphene/YIG with a large interaction, but also enhanced spin-orbit coupling that believed be inherently weak ideal graphene. order can lead novel transport phenomena such...

We report a theoretical study of the influence electron-electron interactions on one-particle Green's function doped graphene sheet based random-phase approximation and graphene's massless Dirac equation continuum model. find that states near point interact strongly with plasmons characteristic frequency ${\ensuremath{\omega}}_{\mathrm{pl}}^{\ensuremath{\star}}$ scales sheet's Fermi energy depends its interaction coupling constant ${\ensuremath{\alpha}}_{\mathrm{gr}}$, partially explaining...

As the only non-carbon elemental layered allotrope, few-layer black phosphorus or phosphorene has emerged as a novel two-dimensional (2D) semiconductor with both high bulk mobility and band gap. Here we report fabrication transport measurements of phosphorene-hexagonal BN (hBN) heterostructures one-dimensional edge contacts. These transistors are stable in ambient conditions for >300 h, display ambipolar behavior, gate-dependent metal–insulator transition, up to 4000 cm2 V−1 s−1. At low...

Graphene is described at low energy by a massless Dirac equation whose eigenstates have definite chirality. We show that the tendency of Coulomb interactions in lightly doped graphene to favor states with larger net chirality leads suppressed spin and charge susceptibilities. Our conclusions are based on an evaluation graphene's exchange random-phase-approximation correlation energies. The suppression consequence quasiparticle switch which enhances velocities near point.

Nickel oxide (NiO) has been studied extensively for various applications ranging from electrochemistry to solar cells [1,2]. In recent years, NiO attracted much attention as an antiferromagnetic (AF) insulator material spintronic devices [3-10]. Understanding the spin - phonon coupling in is a key its functionalization, and enabling AF spintronics' promise of ultra-high-speed low-power dissipation [11,12]. However, despite status exemplary benchmark study correlated electron systems, little...

Interaction driven integer quantum-Hall effects are anticipated in graphene bilayers because of the near degeneracy eight Landau levels which appear neutral system Fermi level. We predict that an intra-Landau-level cyclotron resonance signal will at some odd-integer filling factors, accompanied by collective modes nearly gapless and have approximate k3/2 dispersion. speculate on possibility unusual localization physics associated with these modes.

The quantum valley Hall effect (QVHE) has been observed in a variety of experimental setups, both and classical. While extremely promising for applications, one should be reminded that QVHE is not an exact topological phenomenon that, so far, it fully understood only qualitatively certain extreme limits. Here we present technique to relate systems with spin-Hall insulators accept real-space representations, without taking any limit. Since the bulk-boundary correspondence well latter, are...

The intrinsic spin Hall effect (SHE) originates from the topology of Bloch bands in momentum space. duality between real space and calls for a induced analogy to topological (THE) skyrmions. We theoretically demonstrate (TSHE) which pure transverse current is generated skyrmion texture.

A band-projection formalism is developed for calculating the superfluid weight in two-dimensional multiorbital superconductors with an orbital-dependent pairing. It discovered that, this case, band geometric stiffness tensor can be locally nonpositive definite some regions of Brillouin zone. When these are large enough or include nodal singularities, total becomes due to pairing fluctuations, resulting transition a BCS state pair density wave (PDW). This BCS-PDW studied context two-orbital...

We describe the formation of superconducting states in graphene presence pseudo-Landau-levels induced by strain, when time reversal symmetry is preserved. show that superconductivity strained quantum critical are completely filled, whereas at partial fillings survives weak coupling. In coupling limit, temperature scales linearly with strength and shows a sequence points as function filling factor can be accessed experimentally. argue electron-phonon transition controlled amount strain...

In Lorentz-invariant systems spontaneously broken gauge symmetry results in three types of fundamental excitations: density excitations, Higgs bosons (amplitude modes), and Goldstone (phase modes). The phase modes are coupled by electromagnetic interactions while the amplitude not. $s$-wave superconductors, mode, which can be observed only under special conditions, has been detected. We show that unconventional $d$-wave such as high-temperature cuprate should have a rich assortment bosons,...

Exciton condensation in an electron-hole bilayer system of monolayer transition-metal dichalcogenides is analyzed at three different levels theory to account for screening and quasiparticle renormalization. The large effective masses the transition metal place them a strong coupling regime. In this regime, mean-field (MF) with either unscreened or screened interlayer interaction predicts room-temperature condensate. Interlayer intralayer interactions renormalize dispersion, effect included...

The superfluid weight of an isolated flat band in multiorbital superconductors contains contributions from the band's quantum metric and a lattice geometric term that depends on orbital positions lattice. Since is measure superconductor's energy fluctuation, it independent geometry, leading to minimal [Phys. Rev. B 106, 014518 (2022)]. Here, perturbation approach developed study its dependence for composite bands. When all orbitals exhibit uniform pairing, each contribution interband between...

In this article we review the quantum Hall physics of graphene based two-dimensional electron systems, with a special focus on recent experimental and theoretical developments. We explain why bilayer can be viewed respectively as J=1 J=2 chiral gases (C2DEGs), property frames their physics. The current status work role electron-electron interactions is reviewed at length an emphasis unresolved issues in field, including assessing disorder results. Special attention given to interesting low...

Nonanalytic Bloch eigenstates at isolated band degeneracy points exhibit singular behavior in the quantum metric. Here, a description of superfluid weight for zero-energy flat bands proximity to other high-energy is presented, where they together form gap system. When closes, geometric and conventional contributions as function superconducting different cross-over behaviors. The scaling with studied detail, effect on Berezinskii–Kosterlitz–Thouless transition temperature explored. It found...

In ordinary semiconductor bilayers, exciton condensates appear at total Landau-level filling factor ${\ensuremath{\nu}}_{T}=1$. We predict that similar states will occur in Bernal stacked graphene bilayers many nonzero integer factors. For ${\ensuremath{\nu}}_{T}=\ensuremath{-}3$, 1 we find the superfluid density of condensate vanishes and a finite-temperature fluctuation-induced first order isotropic-smectic phase transition occurs when layer densities are not balanced. These anomalous...

A partially filled Landau level (LL) hosts a variety of correlated states matter with unique properties. The ability to control these phases requires tuning the effective electron interactions within LL, which has been difficult achieve in GaAs-based structures. Here we consider class Dirac materials chiral band structure, along mass term, gives rise wide tunability by magnetic field. This is such that different can occur single and phase transitions between them be driven situ....

As the Fermi level and band structure of two-dimensional materials are readily tunable, they constitute an ideal platform for exploring Lifshitz transition, a change in topology material's surface. Using tetralayer graphene that host two intersecting massive Dirac bands, we demonstrate multiple transitions multiband transport, which manifest as nonmonotonic dependence conductivity on charge density n out-of-plane electric field D, anomalous quantum Hall sequences Landau crossings evolve with n, B.

A graphene bilayer in a transverse magnetic field has set of Landau levels with energies $E=\pm \sqrt{N(N+1)}\hslash \omega_{c}^{\ast}$ where $\omega_{c}^{\ast}$ is the effective cyclotron frequency and $% N=0,1,2,...$ All but N=0 are four times degenerate counting spin valley degrees freedom. The level an extra degeneracy due to fact that orbitals $n=0$ $n=1$ both have zero kinetic energies. At integer filling factors, Coulomb interactions produce broken-symmetry states partial or full...

We calculate the density-density response function and electron self-energy for undoped bilayer graphene within random phase approximation. show that quasiparticle decay rate scales linearly with energy, weight vanishes logarithmically in low-energy limit, indicating non-Fermi-liquid behavior. This is a consequence of absence Fermi surface neutral corresponding larger space available scattering processes. Experimental consequences our results as well their differences from those single-layer...

In a graphene bilayer with Bernal stacking both $n=0$ and $n=1$ orbital Landau levels have zero kinetic energy. An electronic state in the N=0 level consequently has three quantum numbers addition to its guiding center label: spin, valley index $K$ or $K^{\prime}$, an number $n=0,1.$ The two-dimensional electron gas (2DEG) supports wide variety of broken-symmetry states which pseudospins associated these order manner that is dependent on filling factor $\nu $ electric potential difference...