Optical Response of Chiral Multifold Semimetal PdGa

Polatkan, S.; Uykur, Ece

doi:10.3390/cryst11020080

Cited by 5 publications

(5 citation statements)

References 49 publications

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“…For this lattice model, σ inter zz no longer always equals to σ inter xx even at t z = t = m. Interestingly, the Hall conductivity σ yx occurs and a sign change exists in contrast to two longitudinal cases, where σ inter xx and σ inter zz are always positive. In the dc limit, the calculated σ yx agrees with equation (33). The sign change is near ω/m = 1 for both cases.…”

Section: Optical Conductivities Of Lattice Modelssupporting

confidence: 72%

“…The Hall conductivity is almost negative in the entire regime of the optical frequency since the Chern number changes the sign in contrast to the linear case. The dc limit of it fits well with equation (33). Further, the value of it is sufficiently large at about ω/m < 1, but it becomes very small at high optical frequency.…”

Section: Optical Conductivities Of Lattice Modelssupporting

confidence: 72%

“…Habibi et al theoretically included an angular parameter in the Hamiltonian to find the strong angular parameter dependence in both Drude and interband optical conductivities [31]. Also, with the help of the first-principles band calculation, the dynamical conductivities were calculated in CoSi [32] and PdGa [33].…”

Section: Introductionmentioning

confidence: 99%

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Optical conductivities in triple fermions with different monopole charges

Chen¹,

Wang²

2021

J. Phys.: Condens. Matter

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We investigate the linear optical conductivities of the newly-discovered triple-component semimetals. Due to the exactly ﬂat band, the optical conductivity relates to the transition between the zero band and the conduction band directly reﬂecting the band structure of the conduction electrons in contrast to the other materials. For the low-energy models with various monopole charges, the diagonal conductivities show strong anisotropy. The ω-dependence of interband conductivities for a general low-energy model is deduced. The real part of the interband σ_xx always linearly depends on the optical frequency, while the one of σ_zz is proportional to ω^{2/n-1}. This can be a unique ﬁngerprint of the monopole charge. For the lattice models, there also exists the optical anomalous Hall conductivity, where a sign change may appear. The characteristic frequencies of the kink structures are calculated, strictly. Our work will help us to establish the basic picture of linear optical response in topological triple-component semimetals and identify them from other materials.

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Section: Optical Conductivities Of Lattice Modelssupporting

confidence: 72%

Section: Optical Conductivities Of Lattice Modelssupporting

confidence: 72%

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Optical conductivities in triple fermions with different monopole charges

Chen¹,

Wang²

2021

J. Phys.: Condens. Matter

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“…In the absence of SOC we identify bands as X1, X2, X3, X4 are crossing the Fermi energy level as noted in This corroborates the robustness of large linear band relation (∼ 700 meV) in the electronic structure calculations. The summation of isolated conductivities is plotted in the black color render predominantly linear optical conductivity with the frequency from energy range 0.4 to 0.8 eV, suggesting the linear band transitions in PtAl, as observed for the linear band chiral topological systems RhSi, CoSi, PdGa [29,[48][49][50]. The four-fold crossing point in PdGa is found far below the Fermi energy level therefore linear band feature in optical conductivity is observed in the high photon energy regime as compared to the PtAl [48].…”

Section: Electronic Structurementioning

confidence: 81%

Analysis of the unconventional chiral fermions in a non-centrosymmetric chiral crystal $\textbf {PtAl}$

Saini,

Sasmal,

Kulkarni

et al. 2022

Preprint

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Symmetry-protected non-trivial states in chiral topological materials hold immense potential for fundamental science and technological advances. Here, we report electrical transport, quantum oscillations, and electronic structure results of a single crystal of chiral quantum material PtAl. Based on the de Haas-van Alphen (dHvA) oscillations, we show that the smallest Fermi pocket (α) possesses a non-trivial Berry phase 1.16π. The band associated with this Fermi pocket carries a linear energy dispersion over a substantial energy window of ∼700 meV that is further consistent with the calculated optical conductivity. First-principles calculations unfold that PtAl is a higherfold chiral fermion semimetal where structural chirality drives the chiral fermions to lie at the high-symmetry Γ and R points of the cubic Brillouin zone. In the absence of spin-orbit coupling, the band crossings at Γ and R points are three-and four-fold degenerate with a chiral charge of −2 and +2, respectively. The inclusion of spin-orbit coupling transforms these crossing points into four-and six-fold degenerate points with a chiral charge of −4 and +4. Nontrivial surface states on the (001) plane connect the bulk projected chiral points through the long helical Fermi arcs that spread over the entire Brillouin zone.

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“…The transformation of the multifold band crossings into nodes of other types with different topological charges, their shift in energy and in reciprocal space, and the tilt of the dispersion around the nodes are studied in detail, depending on the direction of uniaxial deformation. Polatkan and Uykur [10] present a theoretical study of the band structure and optical conductivity for another multifold semimetal, PdGa. They identify several characteristic features in the optical conductivity and relate their origin to the band structure.…”

mentioning

confidence: 99%