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TT: Fachverband Tiefe Temperaturen

TT 23: Transport: Topological Semimetals 1 (jointly with DS, MA, HL, O)

TT 23.3: Vortrag

Dienstag, 21. März 2017, 10:00–10:15, HSZ 201

Interband optical conductivity of the Dirac semimetal Cd₃As₂ — •D. Neubauer¹, J. P. Carbotte², A. A. Nateprov³, A. Löhle¹, M. Dressel¹, and A. V. Pronin¹ — ¹1. Physikalisches Institut, Universität Stuttgart, Germany — ²Department of Physics and Astronomy, McMaster University, Canada — ³Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, Moldova

We measured the optical reflectivity of [001]-oriented n-doped Cd₃As₂ in a broad frequency range (50 – 22 000 cm⁻¹) for temperatures from 10 to 300 K. The optical conductivity, σ(ω) = σ₁(ω) + iσ₂(ω), is isotropic within the (001) plane; its real part follows a power law, σ₁(ω) ∝ ω^1.65, in a large interval from 2000 to 8000 cm⁻¹. This behavior is caused by interband transitions between two bands, which are effectively described by a sublinear dispersion relation, E(k) ∝ k ^0.6. The momentum-averaged Fermi velocity of the carriers in these bands is energy dependent and ranges from 1.2× 10⁵ to 3 × 10⁵ m/s, depending on the distance from the Dirac points. These values are in agreement with the published data on Cd₃As₂. We detect a gaplike feature in σ₁(ω) and associate it with the Fermi level positioned around 100 meV above the Dirac points. Finally, we compare our results with recent magneto-optical infrared data.