1.   completely quantized 2-D electron gas

2.   GaAsAl_xGa_1-xAs MOSFET

3.   Uses 10T mag. flux dens. at 1K

4.   Requires calculable capacitor and calibration of resistance.
5. Thompson/Lampard, 1956/7 electrostatics theorem; cylindrical capacitor, length dependence only. 25cm movement=0.5pF.

6.   Calculated von Klitzing constant: R_K=h/e²=u₀c/2

7.   137.036 0084(33) or 24 ppb. See NIST.

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