Oscillatory currenthyphen;voltage characteristics ofn+hyphen;GaAs/semihyphen;insulating Al0.8Ga0.2As/nGaAs heterojunction barriers (400 Aring; thick) grown by molecular beam epitaxy onn+hyphen;GaAs (100) substrates are observed at 4 K when the heterostructures are placed under thetransverseuniaxial stress along lang;011rang; direction (perpendicular to current direction) above 4 kbar. We attribute these oscillations to the resonantindirectFowlerndash;Nordheim tunneling via lang;011rang; oriented transverseXvalleys, where the change of wave vector is required for tunneling.
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