Quantum Hall effect on surface states of topological insulator β-Ag<sub>2</sub>Te thin films
Oral-In-person
Abstract
β-Ag2Te is a three-dimensional topological insulator whose surface states exhibit higher carrier mobility and lower carrier density compared to (Bi,Sb)2Te3 [1-3], making it a promising platform for exploring topological quantum transport. However, previous quantum transport studies of β-Ag2Te have been limited to exfoliated nanoflakes, and thin-film growth has so far produced only polycrystalline samples.
Here, we report the molecular beam epitaxy (MBE) growth of high-quality β-Ag2Te thin films and the observation of a dissipationless quantum Hall effect. For the first time in this material, we achieved quantum Hall states with filling factors ν = ±1, characterized by quantized Hall resistance (Ryx = ±h/e²) and zero longitudinal resistance (Rxx ~ 0) at 1.8 K and 10 T in films with thicknesses of 10 nm. These conditions correspond to much higher temperatures and lower magnetic fields than those required for (Bi,Sb)2Te3 films (40 mK and ~14 T) [4]. Our results demonstrate that β-Ag2Te thin films are a promising platform for exploring device architectures relying on the underlying topological nature of surface states in topological insulators.
[1] W. Chang et al., Phys. Rev. Lett. 106, 156808 (2011).
[2] P. Leng et al., Nano Lett. 20, 7004 (2020).
[3] P. Leng et al., Nano Lett. 23, 9026 (2023).
[4] R. Yoshimi et al., Nat. Commun. 6, 6627 (2015).
Here, we report the molecular beam epitaxy (MBE) growth of high-quality β-Ag2Te thin films and the observation of a dissipationless quantum Hall effect. For the first time in this material, we achieved quantum Hall states with filling factors ν = ±1, characterized by quantized Hall resistance (Ryx = ±h/e²) and zero longitudinal resistance (Rxx ~ 0) at 1.8 K and 10 T in films with thicknesses of 10 nm. These conditions correspond to much higher temperatures and lower magnetic fields than those required for (Bi,Sb)2Te3 films (40 mK and ~14 T) [4]. Our results demonstrate that β-Ag2Te thin films are a promising platform for exploring device architectures relying on the underlying topological nature of surface states in topological insulators.
[1] W. Chang et al., Phys. Rev. Lett. 106, 156808 (2011).
[2] P. Leng et al., Nano Lett. 20, 7004 (2020).
[3] P. Leng et al., Nano Lett. 23, 9026 (2023).
[4] R. Yoshimi et al., Nat. Commun. 6, 6627 (2015).
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Presenters
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Mizuki Ohno
- Caltech