Dependence of the 0.5 x (2e(2)/h) conductance plateau on the aspect ratio of InAs quantum point contacts with in-plane side gates

作者：Das P P^*; Jones A; Cahay M^*; Kalita S; Mal S S; Sterin N S; Yadunath T R; Advaitha M; Herbert S T

来源：Journal of Applied Physics, 2017, 121(8): 083901.

DOI：10.1063/1.4977110

The observation of a 0.5 x (2e(2)/h) conductance plateau in asymmetrically biased quantum point contacts (QPCs) with in-plane side gates (SGs) has been attributed to the onset of spin-polarized current through these structures. For InAs QPCs with the same width but a longer channel length, there is roughly a fourfold increase in the range of common sweep voltage applied to the SGs over which the 0.5 x (2e(2)/h) plateau is observed when the QPC aspect ratio (ratio of length over the width of the narrow portion of the structure) is increased by a factor 3. Non-equilibrium Green's function simulations indicate that the increase in the size of the 0.5 x (2e(2)/h) plateau is due to an increased importance, over a larger range of common sweep voltage, of the effects of electronelectron interactions in QPC devices with a larger aspect ratio. The use of asymmetrically biased QPCs with in-plane SGs and large aspect ratio could therefore pave the way to build robust spin injectors and detectors for the successful implementation of spin field effect transistors.

• 出版日期2017-2-28