Electronic transport in the lowest Landau level of disordered graphene sheets placed in a homogeneous perpendicular magnetic field is a long-standing and cumbersome problem which defies a conclusive solution for several years. Because the modeled system lacks an intrinsic small parameter, the theoretical picture is infested with singularities and anomalies. We propose an analytical approach to the conductivity based on the analysis of the diffusive processes, and we calculate the density of states, the diffusion coefficient and the static conductivity. The obtained results are not only interesting from the purely theoretical point of view but have a practical significance as well, especially for the development of the novel high-precision calibration devices.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9145546 | PMC |
http://dx.doi.org/10.3390/nano12101675 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
We revisit the naked transition metal cation (Ti) and methanol reaction and go beyond the standard Landau-Zener (LZ) picture when modeling the intersystem crossing (ISC) rate between the lowest doublet and quartet states. We use both (i) unconstrained Born-Oppenheimer molecular dynamics (BOMD) calculations with an approximate two-state method to estimate population transfer between spin diabats and (ii) constrained dynamics to explore energetically accessible portions of the - 1 crossing seam, where is the total number of internal degrees of freedom. Whereas previous LZ calculations (that necessarily relied on the Condon approximation to be valid) fell short and predicted much slower crossing probabilities than shown in experiment, we show that ISC can occur rapidly because the spin-orbit coupling (SOC) between the doublet and quartet surfaces can vary by 2 orders of magnitude (depending on where in the seam the crossing occurs during dynamics) and the crossing region is revisited multiple times during a dynamics run of a few hundred femtoseconds.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
Space Vehicles Directorate, US Air Force Research Laboratory, Kirtland Air Force Base, Albuquerque, NM 87117, United States of America.
The subject of our present investigation is the collective electronic properties of various types of pseudospin-1 Dirac-cone materials with a flat band and finite bandgaps in their low-energy spectra. Specifically, we have calculated the dynamical polarization, plasmon dispersions, as well as their decay rates due to Landau damping and presented the closed-form analytical expressions for the wave function overlaps for both the gapped dice lattice and the Lieb lattice. The gapped dice lattice is a special case of the more general-T3model such that its band structure is symmetric and the flat band remains dispersionless.
View Article and Find Full Text PDFNat Commun
November 2024
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
In Landau's celebrated Fermi liquid theory, electrons in a metal obey the Wiedemann-Franz law at the lowest temperatures. This law states that electron heat and charge transport are linked by a constant L, i.e.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Department of Physics, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
We perform infrared magnetospectroscopy of Landau level (LL) transitions in dual-gated bilayer graphene. At ν=4 when the zeroth LL (octet) is filled, two resonances are observed indicating the opening of a gap. At ν=0 when the octet is half-filled, multiple resonances disperse nonmonotonically with increasing displacement field, D, perpendicular to the sheet, showing a phase transition at modest displacement fields from a canted antiferromagnet (CAFM) to the layer-polarized state, with a gap that opens linearly in D.
View Article and Find Full Text PDFNature
November 2024
Department of Physics, University of Washington, Seattle, WA, USA.
The half-filled lowest Landau level is a fascinating platform for researching interacting topological phases. A celebrated example is the composite Fermi liquid, a non-Fermi liquid formed by composite fermions in strong magnetic fields. Its zero-field counterpart is predicted in a twisted MoTe bilayer (tMoTe)-a recently discovered fractional Chern insulator exhibiting the fractional quantum anomalous Hall effect.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!