0000000000590879

AUTHOR

Bernardo Uribe

showing 3 related works from this author

Chiralities of nodal points along high symmetry lines with screw rotation symmetry

2021

Screw rotations in nonsymmorphic space group symmetries induce the presence of hourglass and accordion shape band structures along screw invariant lines whenever spin-orbit coupling is nonnegligible. These structures induce topological enforced Weyl points on the band intersections. In this work we show that the chirality of each Weyl point is related to the representations of the cyclic group on the bands that form the intersection. To achieve this, we calculate the Picard group of isomorphism classes of complex line bundles over the 2-dimensional sphere with cyclic group action, and we show how the chirality (Chern number) relates to the eigenvalues of the rotation action on the rotation …

Condensed Matter - Materials ScienceChern classComplex lineMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesCyclic group02 engineering and technology021001 nanoscience & nanotechnologyCoupling (probability)01 natural sciences0103 physical sciencesHomogeneous spaceFOS: MathematicsAlgebraic Topology (math.AT)Equivariant mapMathematics - Algebraic TopologyInvariant (mathematics)Symmetry (geometry)010306 general physics0210 nano-technologyMathematical physics
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Topological electronic structure and Weyl points in nonsymmorphic hexagonal materials

2020

Using topological band theory analysis we show that the nonsymmorphic symmetry operations in hexagonal lattices enforce Weyl points at the screw-invariant high-symmetry lines of the band structure. The corepresentation theory and connectivity group theory show that Weyl points are generated by band crossings in accordion-like and hourglass-like dispersion relations. These Weyl points are stable against weak perturbations and are protected by the screw rotation symmetry. Based on first-principles calculations we found a complete agreement between the topological predicted energy dispersion relations and real hexagonal materials. Topological charge (chirality) and Berry curvature calculations…

Materials scienceSymmetry operationPhysics and Astronomy (miscellaneous)FOS: Physical sciences02 engineering and technologyAlgebraic topologyTopology01 natural sciencesDispersion relationMesoscale and Nanoscale Physics (cond-mat.mes-hall)0103 physical sciencesFOS: MathematicsAlgebraic Topology (math.AT)General Materials ScienceMathematics - Algebraic Topology010306 general physicsTopological quantum numberCondensed Matter - Materials ScienceCondensed Matter - Mesoscale and Nanoscale PhysicsMaterials Science (cond-mat.mtrl-sci)Charge (physics)021001 nanoscience & nanotechnologyCoupling (probability)Berry connection and curvature0210 nano-technologyGroup theory
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Quasinodal lines in rhombohedral magnetic materials

2021

A well-established result in condensed matter physics states that materials crystallizing in symmetry groups containing glide reflection symmetries possess nodal lines on the energy bands. These nodal lines are topologically protected and appear on the fixed planes of the reflection in reciprocal space. In the presence of inversion symmetry, the energy bands are degenerate and the nodal lines on the fixed plane may hybridize or may cross. In the former case, the crossing is avoided, thus producing lines on reciprocal space where the energy gap is small, and in the latter, the nodal lines will endure, thus producing Dirac or double nodal lines. In addition, if the material crystallizes in a …

CrystallographyCondensed Matter - Materials ScienceMaterials scienceCondensed Matter - Mesoscale and Nanoscale PhysicsMesoscale and Nanoscale Physics (cond-mat.mes-hall)FOS: MathematicsMaterials Science (cond-mat.mtrl-sci)Algebraic Topology (math.AT)FOS: Physical sciencesTrigonal crystal systemMathematics - Algebraic Topology
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