Quantum Hall effect on surface states of topological insulator β-Ag<sub>2</sub>Te thin films
ORAL
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).
*This work was supported by the Gordon and Betty Moore Foundation's EPiQS Initiative Grant number GBMF10638, and by Institute for Quantum Information and Matter, an NSF Physics Frontiers Center, Grant PHY-1733907.
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Presenters
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Mizuki Ohno
- Caltech