The Puzzle of the 0.7 Anomaly in Conductance of Quantum Point Contact Reexamined

Abstract

Apart from usual quantization steps in the conductance of 1D systems, equal to G0 = 2e /h [1], an additional plateau-like feature appears at a fraction of about 0.7 below the rst conductance step in GaAs-based quantum point contacts (QPCs) [2, 3]. Despite a huge number of research works devoted to this anomalous feature, its origin remains still unclear [4]. Here, an unique explanation of this anomaly is proposed, which relies on the fundamental principles of quantum mechanics: superposition and interference of (spin) states.