Semiconductors successfully induce helium field and valley currents by distorting graphene
Distortion induced strain magnetic field in graphene nanoribbons One of the most important features of the graphene electronic structure is the dual degree of freedom known as the valley spin. How to realize "valley" spin polarized flow in graphene system has been an important target in the research field of graphene in recent years. People expect quantum manipulation of "Valley" spin freedom so that it can be applied to future information technology. Recently, it was found that the inhomogeneous mechanical strain in graphene can induce a helium field, which is equal in magnitude but opposite in the two energy valleys K and K'. Experimentally, it has been demonstrated that the helium field can reach 300T, far exceeding the stable magnetic field (about 45T) that human beings can achieve in the laboratory. Therefore, how to generate non-uniform strain in graphene, and then generate the design of the helium field and realize the manipulation of “valley†spin are the hot issues in the field of graphene research in recent years. Chang Kai, a researcher of the State Key Laboratory of Superlattices at the Institute of Semiconductors of the Chinese Academy of Sciences, and Dr. Zhang Dongbo from the Beijing Center for Computational Sciences and Research recently proposed a new scheme, a twisted graphene band. This solution proposes transferring or depositing graphene onto a flexible substrate, which results in a non-uniform magnetic field by distorting the flexible substrate to produce a non-uniform strain field. For the first time, they used the DFTB method to calculate the electronic structure of the graphene ribbons with a width of 100 nanometers. It was found that both the sawtooth edge and the nanobands on the armchair side have edge states induced by the helium magnetic field. This type of edge state does not depend on the shape of the boundary, but is also a pure “valley†edge state, ie, the K-valley electrons flow in one direction, and the K′ valley flows in the opposite direction. The valley currents on the two sides of the border are in opposite directions. At the same time, the existence of a snake orbit was found in the distorted graphene center. Surprisingly, a stable magnetic field of up to 180 T can be generated in the graphene band by a small mechanical distortion (approximately 60 degrees). 9006(Hb4) Led Headlight,Hb4 Led Headlight,9006 Led Headlight,Hb4 Headlight CHANGZHOU CLD AUTO ELECTRICAL CO.,LTD , https://www.cld-led.com