Nonequilibrium electronic transports through a system hosting three quantum dots hybridized with superconductors are investigated. By tuning the relative positions of the dot levels, we illustrate the existence of Maj...Nonequilibrium electronic transports through a system hosting three quantum dots hybridized with superconductors are investigated. By tuning the relative positions of the dot levels, we illustrate the existence of Majorana fermions and show that the Majorana feimions will either survive separately on single dots or distribute themselves among different dots with tunable probabilities. As a result, different physical mechanisms appear, including local Andreev reflection（LAR）,cross Andreev reflection（CAR）, and cross resonant tunneling（CRT）. The resulting characteristics may be used to reveal the unique properties of Majorana fermions. In addition, we discuss the spin-polarized transports and find a pure spin current and a spin filter effect due to the joint effect of CRT and CAR, which is important for designing spintronic devices.展开更多
We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling ...We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted： observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electricalIy controlled magnetization switching.展开更多
平面霍尔效应(planar Hall effect,PHE)是当前凝聚态输运中研究的热点之一.近年来,平面霍尔效应,尤其是拓扑材料中的平面霍尔效应,引起了人们的广泛关注和研究,并取得了很大的进展.不同于普通霍尔效应,平面霍尔效应中的横向电流、磁场...平面霍尔效应(planar Hall effect,PHE)是当前凝聚态输运中研究的热点之一.近年来,平面霍尔效应,尤其是拓扑材料中的平面霍尔效应,引起了人们的广泛关注和研究,并取得了很大的进展.不同于普通霍尔效应,平面霍尔效应中的横向电流、磁场和电场可以出现在同一平面,无法用洛伦兹力解释,其很大程度上依赖于磁电阻的各向异性.本文从理论和实验两个角度介绍拓扑材料中平面霍尔效应的研究进展,深入分析了导致线性和非线性平面霍尔效应的各种外禀和内禀机制,并讨论尚待解决的相关问题和未来的发展方向.展开更多
基金supported by the New Century Excellent Talents in University of China(Grant No.NCET-10-0090)the National Natural Science Foundation of China(Grant Nos.11474106,11174088,and 11274124)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University of China(Grant No.IRT1243)the Natural Science Foundation of Guangdong Province,China(Grant No.S2012010010681)
文摘Nonequilibrium electronic transports through a system hosting three quantum dots hybridized with superconductors are investigated. By tuning the relative positions of the dot levels, we illustrate the existence of Majorana fermions and show that the Majorana feimions will either survive separately on single dots or distribute themselves among different dots with tunable probabilities. As a result, different physical mechanisms appear, including local Andreev reflection（LAR）,cross Andreev reflection（CAR）, and cross resonant tunneling（CRT）. The resulting characteristics may be used to reveal the unique properties of Majorana fermions. In addition, we discuss the spin-polarized transports and find a pure spin current and a spin filter effect due to the joint effect of CRT and CAR, which is important for designing spintronic devices.
基金Supported by National Natural Science Foundation of China under Grant Nos.11174088,11175067,11274124
文摘We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topologicM insulator. The current-voltage characteristic curve and the tunneling conductance are calculated theoretically. Two interesting transport features are predicted： observable negative differential conductances and linear conductances tunable from unit to nearly zero. These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization. Our results may contribute to the development of high-speed switching and functional applications or electricalIy controlled magnetization switching.
文摘平面霍尔效应(planar Hall effect,PHE)是当前凝聚态输运中研究的热点之一.近年来,平面霍尔效应,尤其是拓扑材料中的平面霍尔效应,引起了人们的广泛关注和研究,并取得了很大的进展.不同于普通霍尔效应,平面霍尔效应中的横向电流、磁场和电场可以出现在同一平面,无法用洛伦兹力解释,其很大程度上依赖于磁电阻的各向异性.本文从理论和实验两个角度介绍拓扑材料中平面霍尔效应的研究进展,深入分析了导致线性和非线性平面霍尔效应的各种外禀和内禀机制,并讨论尚待解决的相关问题和未来的发展方向.
