Universal peak conductivities at the transition between insulating and integer quantum Hall states

Murzin, S. S.; Jansen, A. G. M.

doi:10.1016/j.physe.2011.04.008

Cited by 2 publications

(1 citation statement)

References 28 publications

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“…S14 for σxx values between the n = 0 Landau levels [24]). Interestingly, this σxx value is close to twice of the universal value of 0.5 e 2 /h [42], consistent with the crossing of two Landau levels -by contrast, at the other quantum Hall transitions, σxx is close to 0.5 e 2 /h. (we note that G, presented in Fig.…”

Section: Appendix A: Temperature Dependent Conductance At ν = 0 In Th...supporting

confidence: 75%

Two-Dimensional Topological Insulator State in Cadmium Arsenide Thin Films

Lygo

Guo²,

Rashidi³

et al. 2023

Phys. Rev. Lett.

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Two-dimensional topological insulators (2D TIs) are a highly desired quantum phase but few materials have demonstrated clear signatures of a 2D TI state. It has been predicted that 2DTIs can be created from thin films of three-dimensional TIs by reducing the film thickness until the surface states hybridize. Here, we employ this technique to report the first observation of a 2D TI state in epitaxial thin films of cadmium arsenide, a prototype Dirac semimetal in bulk form.Using magnetotransport measurements with electrostatic gating, we observe a Landau level spectrum and quantum Hall effect that are in excellent agreement with those of an ideal 2D TI. Specifically, we observe a crossing of the zeroth Landau levels at a critical magnetic field. We show that the film thickness can be used to tune the critical magnetic field. Moreover, a larger change in film thickness causes a transition from a 2D TI to a 2D trivial insulator, just as predicted by theory. The high degree of tunability available in epitaxial cadmium arsenide heterostructures can thus be used to fine-tune the 2D TI, which is essential for future topological devices.

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Section: Appendix A: Temperature Dependent Conductance At ν = 0 In Th...supporting

confidence: 75%

Two-Dimensional Topological Insulator State in Cadmium Arsenide Thin Films

Lygo

Guo²,

Rashidi³

et al. 2023

Phys. Rev. Lett.

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ν = 0 quantum Hall state in a cadmium arsenide thin film

et al. 2022

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Graphene and topological insulators can feature a unique quantum Hall state with a filling factor of ν = 0 that supplies a wealth of information about the nature of the underlying electronic states. Here, we report on the observation of a ν = 0 Hall state in magnetotransport experiments on a 20-nm-thin, (001)-oriented cadmium arsenide film that is tuned by a gate voltage. While cadmium arsenide is a topological semimetal as a bulk material, thin films can host topological insulator phases. At high magnetic fields, we observe a highly resistive ν = 0 Hall state that we attribute to a widening gap between two zeroth Landau levels as the magnetic field is increased. We discuss possible scenarios that could give rise to the lifting of the degeneracy of zeroth Landau levels. Our results are most consistent with a scenario of hybridization of the topological surface states induced by quantum confinement.

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Universal peak conductivities at the transition between insulating and integer quantum Hall states

Cited by 2 publications

References 28 publications

Two-Dimensional Topological Insulator State in Cadmium Arsenide Thin Films

Two-Dimensional Topological Insulator State in Cadmium Arsenide Thin Films

ν = 0 quantum Hall state in a cadmium arsenide thin film

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