Quantized Conductance in a CVD-Grown Nanoribbon with Hidden Rashba Effect

Quantized conductance in quasi-one-dimensional systems not only provides a hallmark of ballistic transport, but also serves as a gateway for exploring quantum phenomena. Recently, a unique hidden Rashba effect, which arises from the compensation of opposite spin polarizations of a Rashba bilayer in inversion symmetric crystals with dipole fields, such as bismuth oxyselenide (Bi_{2}O_{2}Se), has attracted tremendous attention. However, investigating this effect utilizing conductance quantization remains challenging. Here we report the conductance quantization observed in a chemical vapor deposition (CVD)-grown high-mobility Bi_{2}O_{2}Se nanoribbon, where quantized conductance plateaus up to 44×2e^{2}/h (e is the elementary charge, h is the Planck's constant, and the factor 2 results from spin degeneracy) are achieved at zero magnetic field. Because of the hidden Rashba effect, the quantized conductance remains in multiples of 2e^{2}/h without Zeeman splitting even under magnetic field up to 12 T. Moreover, within a specific range of magnetic field, the plateau sequence follows the Pascal triangle series, namely, (1,3,6,10,15…)×2e^{2}/h, reflecting the interplay of size quantization in the two transverse directions. These observations are well captured by an effective hidden Rashba bilayer model. Our results demonstrate Bi_{2}O_{2}Se as a compelling platform for spintronics and the investigation of emergent phenomena.