AWhat changed
Kang and colleagues combined local and nonlocal transport with penetration-capacitance measurements in twisted bilayer WSe2. Near hole fillings 2 and 4, local resistances approached h/(2e²) and h/(4e²), while nonlocal responses and bulk incompressibility supported one and two pairs of helical edge channels. The transport changed much more strongly under in-plane than out-of-plane magnetic fields, consistent with approximate spin-conservation protection of a double quantum spin-Hall phase at filling 4.
Scientific scope
Kang and colleagues combined local and nonlocal transport with penetration-capacitance measurements in twisted bilayer WSe2. Near hole fillings 2 and 4, local resistances approached h/(2e²) and h/(4e²), while nonlocal responses and bulk incompressibility supported one and two pairs of helical edge channels. The transport changed much more strongly under in-plane than out-of-plane magnetic fields, consistent with approximate spin-conservation protection of a double quantum spin-Hall phase at filling 4. The evidence is from the February 2024 preprint and selected uniform regions of finite devices. Local resistance exceeded ideal values by about 10–15 percent, and nonlocal resistance was substantially below ideal edge-only predictions. Bulk capacitance and transport came from different devices. Spin Chern numbers and protection are interpreted using a continuum model and approximate Ising spin conservation; exact spin-resolved quantization, arbitrary-disorder robustness and dissipation-free device operation were not established.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The evidence is from the February 2024 preprint and selected uniform regions of finite devices. Local resistance exceeded ideal values by about 10–15 percent, and nonlocal resistance was substantially below ideal edge-only predictions. Bulk capacitance and transport came from different devices. Spin Chern numbers and protection are interpreted using a continuum model and approximate Ising spin conservation; exact spin-resolved quantization, arbitrary-disorder robustness and dissipation-free device operation were not established.
Contributors
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