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Abstract |
We report on the anomalous screening by Dirac states in topological HgTe/CdHgTe heterojunctions in large transverse electric fields[1]. It is mesured in high frequency electronic compressibility experiments. Screening extends over a large chemical potentialrange of 300 meV widely exceeding the 30 meV bulk band gap of HgTe. Dirac screening breakdown is accompanied by an abrupt drop of the Dirac fermion mobility which we attribute to the existence of a series of massive interface states first introduced by Volkov and Pankratov (VP) [2]. Field-effect compressibility is a convenient scattering spectroscopy tool to investigate VP states. Their spectrum obbeys a Landau level energy series with a pseudo magnetic field determined by the Dirac fermon velocity and electric field [3].
[1] A. Inhofer et al., Phys. Rev. B 96, 195104 (2017).
[2] B.A. Volkov, O.A. Pankratov, JETP Lett. 42, 178 (1985).
[3] S. Tchoumakov et al., Phys. Rev. B 96, 201302-R (2017). |
