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The optical conductivity of the new Dirac semimetal candidate Ir$_2$In$_8$Se is measured in a frequency range from 40 to 30000 cm$^{-1}$ at temperatures from 300 K down to 10 K. The measurement reveals that the compound is a low carrier…

Strongly Correlated Electrons · Physics 2022-09-15 S. X. Xu , H. Q. Pi , R. S. Li , T. C. Hu , Q. Wu , D. Wu , H. M. Weng , N. L. Wang

The optical conductivity of MgB$_2$ has been determined on a dense polycrystalline sample in the spectral range 6 meV - 4.6 eV using a combination of ellipsometric and normal incidence reflectivity measurements. $\sigma_{1}(\omega)$…

The optical properties of YNi$_2$B$_2$C are studied by using the first-principles full-potential linearized augmented plane wave (FLAPW) method within the local density approximation. Anisotropic behavior is obtained in the optical…

Superconductivity · Physics 2009-11-07 S. J. Youn , B. I. Min , A. J. Freeman

Superconductivity of the second kind was observed in many 3D Weyl and Dirac semi-metals. However in PdT e2, superconductivity is clearly of the first kind. This is very rare in Dirac semi - metals, but is expected in clean conventional…

Superconductivity · Physics 2018-08-15 B. Ya. Shapiro , I. Shapiro , Dingping Li , Baruch Rosenstein

The optical conductivity, $\sigma(\omega)$, of the two dimensional one-band Hubbard model is calculated at finite temperature using exact diagonalization techniques on finite clusters. The in-plane d.c. resistivity, $\rho_{ab}$, is also…

Condensed Matter · Physics 2009-10-22 Jose A. Riera , Elbio Dagotto

We show that a two-band model with ${\bf k}$-dependent superconducting gaps well describes the transmission and optical conductivity measured for MgB$_2$ thin films. It is also shown that the two-band anisotropic model consistently…

Superconductivity · Physics 2009-11-10 Takashi Yanagisawa , Hajime Shibata

We derived closed-form analytical expressions for the surface response functions (SRFs) for heterostructure. We investigate structures consisting of up to three layered, coated heterostructure of two-dimensional (2D) materials with a…

Mesoscale and Nanoscale Physics · Physics 2026-04-08 Teresa Lee , Godfrey Gumbs , Thi Nga Do , Andrii Iurov , Danhong Huang

We investigate the optical conductivity and far-infrared magneto-optical response of BaNiS$_2$, a simple square-lattice semimetal characterized by Dirac nodal lines that disperse exclusively along the out-of-plane direction. With the…

Two-dimensional (2D) massless Dirac electrons appear on a surface of three-dimensional topological insulators. The conductivity of such a 2D Dirac electron system is studied for strong topological insulators in the case of the Fermi level…

Mesoscale and Nanoscale Physics · Physics 2016-09-21 Yositake Takane

We investigate the transport signatures of pseudo-Landau levels (PLLs) in two-dimensional anisotropic Dirac systems with tilted cones, whose effective bandstructure results from strain-induced pseudogauge fields. In contrast to conventional…

Mesoscale and Nanoscale Physics · Physics 2026-04-29 Sanskar Sharma , Ipsita Mandal

Two-dimensional (2D) Dirac fermions occur ubiquitously in condensed matter systems from topological phases to quantum critical points. Since the advent of topological semimetals, where the dispersion is often tilted around the band crossing…

Disordered Systems and Neural Networks · Physics 2025-12-11 Swadeepan Nanda , Pavan Hosur

We investigate electronic transport through exfoliated multilayers of CrSBr, a 2D semiconductor that is attracting attention because of its magnetic properties. We find an extremely pronounced anisotropy that manifests itself in qualitative…

Intense laser-driven nonlinear optical phenomena in two-dimensional (2D) nodal-line semimetals (NLS) exhibit complex mechanisms, particularly in the NbSi$_{x}$Te$_{2}$ material systems characterized by nonsymmorphic symmetry-protected band…

Optics · Physics 2025-08-25 Navdeep Rana , M. S. Mrudul , Amar Bharti , Sucharita Giri , Gopal Dixit

Surface morphology of high mobility heterostructures is examined and correlated with d.c. transport. {\it All} samples examined show evidence of lines in the [1$\bar{1}$0] direction with roughness ranging from small amplitude features to…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 R. L. Willett , J. W. P. Hsu , D. Natelson , K. W. West , L. N. Pfeiffer

Molecular alignment underpins optical, mechanical, and thermal properties of materials, however, its direct measurement from volumes with micrometer dimensions is not accessible, especially, for structurally complex bio-materials. How the…

It is usually supposed that only low-symmetry two-dimensional (2D) materials exhibit anisotropy, here we show that high-symmetry 2D semiconductors can show significant anisotropy in momentum space due to the band structure anisotropy in…

The electrical conductivity anisotropy of the sigma-bands is calculated for the (Mg,Sc)B2 system using a virtual crystal model. Our results reveal that anisotropy drops with relatively little scandium content (< 30%); this behaviour…

Superconductivity · Physics 2007-05-23 Sabina Ruiz-Chavarria , Gustavo Tavizon , Pablo de la Mora

A multifold Hopf semimetal is a topological point node semimetal possessing an anisotropy in the internal electronic structure, e.g., the dipole structure of the Berry curvature. In this paper, the unique features of threefold Hopf…

Mesoscale and Nanoscale Physics · Physics 2023-01-18 Tetsuro Habe

The electronic and optical conductivities for anisotropic tilted Dirac semimetals are calculated using the Kubo formula. As in graphene, it is shown that the minimal conductivity is sensitive to the order in which the temperature, frequency…

Mesoscale and Nanoscale Physics · Physics 2019-11-22 Saúl A. Herrera , Gerardo G. Naumis

The intrinsically superconducting Dirac semimetal 2M-WS$_{2}$ is a promising candidate to realize proximity-induced topological superconductivity in its protected surface states. A precise characterization of the bulk superconducting state…