Topological semimetals in InAs/GaInSb superlattices at room temperature

A linear energy-momentum spectrum of quasiparticles is produced in single crystals of zero-gap InAs/GaInSb superlattices (SL) grown by MBE on GaSb(100) substrates. Dirac nodes are formed by the crossings of the the s-like (E1) and p-like (H1) SL subbands along the [100] growth direction of the crystal. A conduction subband bandwidth of about 80 meV is obtained by employing the pseudomorphically strained GaInSb layers, which also creates the conditions for a temperature-stable Dirac semimetal phase from the room to deep cryogenic temperatures. Magnetotransport of the SL samples is characterized at $\mathrm{T}=4-300\mathrm{K}$ and magnetic fields $\mathrm{B} . Magne-toresitance measurements demonstrated a semimetallic behavior with the 980% increase in the magnetoresistance in a magnetic field of $\mathrm{B}=8\mathrm{T}$ at the room temperature. At $\mathrm{T} Shubnikov - de Haas magneto-oscillations have been observed. Analysis of the Shubnikov - de Haas oscillatory components of the magnetoresistance and the theoretical modeling of the energy-band structure using the eight-band k·p method in the envelope function approximation indicate the presence of quasiparticles with a linear energy dispersion. The topological semimetals in InAs/GaInSb SLs at room temperature could provide a platform for testing new concepts of electronic and optoelectronic devices.