Approaching Quantization in Macroscopic Quantum Spin Hall Devices through Gate Training
Lunczer, Lukas; Leubner, Philipp; Endres, Martin; Muller, Valentin L; Brüne, Christoph; Buhmann, Hartmut; Molenkamp, Laurens W
Journal article, Peer reviewed
Accepted version
Åpne
Permanent lenke
http://hdl.handle.net/11250/2636487Utgivelsesdato
2019Metadata
Vis full innførselSamlinger
- Institutt for fysikk [2652]
- Publikasjoner fra CRIStin - NTNU [37212]
Originalversjon
Physical Review Letters. 2019, 123 (4), 047701-1-047701-5. 10.1103/PhysRevLett.123.047701Sammendrag
Quantum spin Hall edge channels hold great promise as dissipationless one-dimensional conductors.However, the ideal quantized conductance of2e2=his only found in very short channels-in contradictionwith the expected protection against backscattering of the topological insulator state. In this Letter we showthat enhancing the band gap does not improve quantization. When we instead alter the potential landscapeby charging trap states in the gate dielectric using gate training, we approach conductance quantization formacroscopically long channels. Effectively, the scattering length increases to175μm, more than 1 order ofmagnitude longer than in previous works for HgTe-based quantum wells. Our experiments show that thedistortion of the potential landscape by impurities, leading to puddle formation in the narrow gap material,is the major obstacle for observing undisturbed quantum spin Hall edge channel transport