The conductance of quantum point contacts (QPCs) subject to strongly nonlinear source-drain biasing is investigated with transient pulses. The authors investigations reveal the presence of a characteristic fixed point, at which the transient conductance (Gt) is bias independent. This point corresponds to the situation where the unbiased QPC is almost depopulated and can apparently be accounted for by considering the unidirectional population of QPC subbands by the transient voltage. To discuss the variations of Gt away from the fixed point, it is necessary to consider the influence of the applied bias on the QPC profile and electron-phonon scattering.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)