Optical detection of the quantum Hall effect in silicon nanostructures

Electroluminescence spectra of a silicon nanostructure with edge channels covered by chains of dipole centers with negative correlation energy are demonstrated. The presence of such chains provides conditions for nondissipative transport of single charge carriers at high temperatures up to room temperature. Due to the suppression of the electron-electron interactions, the macroscopic quantum phenomena such as Shubnikov - de Haas oscillations and the quantum staircase of Hall resistance are consistent with the positions of the spectral peaks of the detected electroluminescence. The obtained results are considered in the framework of Faraday electromagnetic induction, which indicates that Landau quantization leads to the emergence of induced irradiation similar to Josephson and Andreev generation. Moreover, the detected maxima in the spectral characteristics correspond to odd fractional values of the resistance quantum staircases, while the dips in the electroluminescence spectra are observed at even fractional values of the resistance quantum ladder, which is due to the increased formation of composite bosons and fermions, respectively.

💡 Research Summary

The paper reports a novel approach to detecting both integer and fractional quantum Hall effects (QHE) in a silicon nanostructure by means of infrared electroluminescence spectroscopy. The authors fabricate a “silicon nanosandwich” consisting of an ultra‑narrow (2 nm) quantum well on a (100) silicon substrate, whose edge channels are covered by quasi‑one‑dimensional chains of boron dipole centers (B⁺–B⁻) possessing negative correlation energy (negative‑U). These dipole chains act as an energy reservoir that suppresses electron‑electron interactions and segment the edge channels into discrete “pixels” each containing a single charge carrier. As a result, non‑dissipative transport is achieved up to room temperature.

Electrical measurements performed at 77 K with a 10 nA drain‑source current reveal clear Shubnikov‑de Haas oscillations and a quantum staircase in the Hall resistance. By analyzing the magnetic‑field dependence, the authors extract a two‑dimensional carrier density of 3 × 10¹³ m⁻², pixel dimensions of roughly 2 nm × 16.6 µm, and a total of 124 pixels between the voltage contacts. They propose a Faraday‑induction framework in which the change in carrier energy dE = I_gen · ΔΦ · S (with ΔΦ = m Φ₀, Φ₀ = h/e) links the quantized magnetic flux to the step height of the Hall resistance. The load resistance R_N is identified with the quantum resistance h/e², allowing the model to describe both integer and fractional QHE (e.g., 1/3, 2/5) by associating each step with the capture of a discrete number of flux quanta by a pixel.

Optical detection is carried out using a Bruker Vertex 70 FTIR spectrometer at 300 K under the same drain current, which induces a magnetic field within the edge‑channel pixels. The resulting electroluminescence spectra extend from the mid‑infrared to the terahertz region and display distinct peaks and dips that align precisely with the magnetic‑field positions of the Hall resistance steps. Peaks correspond to odd fractional values of the resistance ladder (e.g., 1/3, 2/3), indicating stimulated emission associated with the formation of composite bosons. Conversely, dips appear at even fractional values (e.g., 2/5, 4/7), which the authors attribute to enhanced formation of composite fermions that increase electron‑electron interaction and quench luminescence.

The authors interpret these observations as evidence of Josephson‑ and Andreev‑like electromagnetic induction processes occurring between the negative‑U dipole chains on opposite edges of each pixel. The induced generation current, together with the quantized flux, selects specific emission wavelengths that match the magnetic‑field scale of the Hall staircase. This unified picture links Landau quantization, non‑dissipative transport, and terahertz emission in a single framework.

In conclusion, the study demonstrates that (i) negative‑U dipole chains can enable high‑temperature, near‑dissipationless transport in silicon nanostructures, (ii) the quantum Hall effect can be optically detected via terahertz electroluminescence whose spectral features map directly onto the integer and fractional Hall resistance steps, and (iii) a Faraday‑induction model provides a coherent theoretical description of the observed phenomena. The work opens avenues for room‑temperature quantum electronic devices and terahertz sources based on silicon, while highlighting the need for precise control of dipole‑chain formation, long‑term stability at elevated temperatures, and quantitative validation of the proposed induction model.