Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

Abstract

Prototypical three-dimensional (3D) topological Dirac semimetals (DSMs), such as Cd${}_3$As${}_2$ and Na${}_3$Bi, contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum dimensions. Despite being extensively studied in recent years, the inherent \emph{Fermi velocity anisotropy} has often been neglected in the theoretical and numerical studies of 3D DSMs. Although this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs, it does \emph{quantitatively} change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics applications. Here we study the linear optical response of 3D DSMs for general Fermi velocity values along each direction. Although the signature conductivity-frequency scaling, $\sigma (\omega )\propto \omega$, of 3D Dirac fermion is well-protected from Fermi velocity anisotropy, the linear optical response exhibits strong linear dichroism as captured by the \emph{universal} extinction ratio scaling law, ${\Lambda }_{ij}=(v_i/v_j{)}^2$ (where $i\ne j$ denotes the three spatial coordinates $x,y,z$, and $v_i$ is the $i$-direction Fermi velocity), which is independent of frequency, temperature, doping, and carrier scattering lifetime. For Cd${}_3$As${}_2$ and Na${}_3$Bi${}_3$, an exceptionally strong extinction ratio larger than 15 and covering broad terahertz window is revealed. Our findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities, such as photodetection and light modulation.

arXiv comment8 pages, 3 figures

References in corpus (40)

• Graphene plasmonics: A platform for strong light-matter interaction
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• Gate-tuning of graphene plasmons revealed by infrared nano-imaging
• Optical nano-imaging of gate-tuneable graphene plasmons
• Graphene Mode-Locked Ultrafast Laser
• Dirac semimetal and topological phase transitions in A3Bi (A=Na, K, Rb)
• Dirac semimetal in three dimensions
• Theoretical Discovery/Prediction: Weyl Semimetal states in the TaAs material (TaAs, NbAs, NbP, TaP) class
• Observation of a topological 3D Dirac semimetal phase in high-mobility Cd3As2
• Graphene Plasmonics: Challenges and Opportunities
• Experimental Realization of a Three-Dimensional Dirac Semimetal
• Phase transition between the quantum spin Hall and insulator phases in 3D: emergence of a topological gapless phase
• Strong nonlinear optical response of graphene flakes measured by four-wave mixing
• Classification of stable three-dimensional Dirac semimetals with nontrivial topology
• Topological nodal line semimetals
• Topological Semimetals
• Topological Phase Transition and Texture Inversion in a Tunable Topological Insulator
• Sub 200fs pulse generation from a graphene mode-locked fiber laser
• Non-linear electromagnetic response of graphene
• First Principles Studies on 3-Dimentional Strong Topological Insulators: Bi2Te3, Bi2Se3 and Sb2Te3
• Dielectric response and novel electromagnetic modes in three-dimensional Dirac semimetal films
• Transition-Metal Pentatelluride ZrTe${}_5$ and HfTe${}_5$: a Paradigm for Large-gap Quantum Spin Hall Insulators
• Tm-doped fiber laser mode-locked by graphene-polymer composite
• Unexpected mass acquisition of Dirac fermions at the quantum phase transition of a topological insulator
• A High-Performance Mid-infrared Optical Switch Enabled by Bulk Dirac Fermions in Cd3As2
• Ultrafast Broadband Photodetectors based on Three-dimensional Dirac Semimetal Cd3As2
• Bulk Dirac points in distorted spinels
• Tuning phase transition between quantum spin Hall and ordinary insulating phases
• Theory of graphene saturable absorption
• Efficient Terahertz Harmonic Generation with Coherent Acceleration of Electrons in the Dirac Semimetal Cd3As2
• Universal phase diagrams for the quantum spin Hall systems
• Non-perturbative high-harmonic generation in the three-dimensional Dirac semimetal Cd${}_3$As${}_2$
• 3D Dirac semimetal Cd3As2: A review of material properties
• Electric control of topological phase transitions in Dirac semimetal thin films
• Many-body effects and ultraviolet renormalization in three-dimensional Dirac materials
• Interacting Dirac liquid in three-dimensional semimetals
• Electron Transport in Dirac and Weyl Semimetals
• Negative differential resistance and characteristic nonlinear electromagnetic response of a Topological Insulator
• Strong anisotropic optical conductivity in two dimensional puckered structures: The role of Rashba effect
• Topological transport in Dirac electronic systems: A concise review

Cited by in corpus (5)

• Terahertz Polarization Conversion from Optical Dichroism in a Topological Dirac Semimetal
• Evidence of 3D Dirac conical bands in TlBiSSe by optical and magneto-optical spectroscopy
• Giant anisotropic photocurrent modulated by strain in type-II Weyl semimetal Td-MoTe2
• Exploring Spectral Singularities in Dirac Semimetals: The Role of Non-Hermitian Physics and Dichroism
• Generation of Half-Integer Harmonics and Efficient THz-to-Visible Frequency Conversion in Strained Graphene