title: Quantum ratchet in two-dimensional semiconductors with Rashba spin-orbit interaction.
abstract: Ratchet is a device that produces direct current of particles when driven by an unbiased force. We demonstrate a simple scattering quantum ratchet based on an asymmetrical quantum tunneling effect in two-dimensional electron gas with Rashba spin-orbit interaction (R2DEG). We consider the tunneling of electrons across a square potential barrier sandwiched by interface scattering potentials of unequal strengths on its either sides. It is found that while the intra-spin tunneling probabilities remain unchanged, the inter-spin-subband tunneling probabilities of electrons crossing the barrier in one direction is unequal to that of the opposite direction. Hence, when the system is driven by an unbiased periodic force, a directional flow of electron current is generated. The scattering quantum ratchet in R2DEG is conceptually simple and is capable of converting a.c. driving force into a rectified current without the need of additional symmetry breaking mechanism or external magnetic field.
authors.affiliation: School of Physics, University of Wollongong, New South Wales 2522, Australia.
authors.forename: Yee Sin
authors.initials: YS
authors.lastname: Ang
authors.affiliation: 1] School of Physics, Peking University, Beijing 100871, China [2] Collaborative Innovation Center of Quantum Matter, Beijing, 100871, China and.
authors.forename: Zhongshui
authors.initials: Z
authors.lastname: Ma
authors.affiliation: 1] School of Physics, University of Wollongong, New South Wales 2522, Australia [2] Cooperative Innovation Center on Terahhertz Science and Technology, Chengdu, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang