We consider several classes of symmetries of the Dirac Hamiltonian in 3 + 1 dimensions, with axially deformed scalar and vector potentials. The symmetries include the known pseudospin and spin limits and additional symmetries which occur when the potentials depend on different variables. Supersymmetries are observed within each class and the corresponding charges are identified.
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http://dx.doi.org/10.1103/PhysRevLett.103.042502 | DOI Listing |
Nano Lett
January 2025
Beijing Computational Science Research Center, Beijing 100193, China.
Artificial honeycomb lattices are essential for understanding exotic quantum phenomena arising from the interplay between Dirac physics and electron correlation. This work shows that the top two moiré valence bands in rhombohedral-stacked twisted MoS bilayers (tb-MoS) form a honeycomb lattice with massless Dirac fermions. The hopping and Coulomb interaction parameters are explicitly determined based on large-scale ab initio calculations.
View Article and Find Full Text PDFPhys Rev Lett
November 2024
Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan 70101, Taiwan.
J Phys Condens Matter
December 2024
Department of Physics, University of Allahabad, Prayagraj 211002, India.
The irradiation of topological insulator surface with elliptically polarized light modifies the topological properties in a phase-dependent manner impacting the Floquet Chern number which is a crucial topological invariant associated with such driven systems. Employing Floquet theory in presence of hexagonal warping term in the Dirac fermion Hamiltonian under off-resonant conditions, we derive an effective Hamiltonian that highlights distinct features in the Floquet-Dirac surface states. Specifically, we identify a helicity and ellipticity-dependent mass term in the quasi-static Hamiltonian, breaking time reversal symmetry.
View Article and Find Full Text PDFPhys Rev Lett
October 2024
Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
This Letter presents a theory of interaction-induced band-flattening in strongly correlated electron systems. We begin by illustrating an inherent connection between flat bands and index theorems, and presenting a generic prescription for constructing flat bands by periodically repeating local Hamiltonians with topological zero modes. Specifically, we demonstrate that a Dirac particle in an external, spatially periodic magnetic field can be cast in this form.
View Article and Find Full Text PDFPhys Rev Lett
September 2024
School of Physics & State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, China.
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