Abstract Spin-valley transport and magnetoresistance are investigated in silicene-based N/TB/N/TB/N junction where N and TB are normal silicene and topological barriers. The topological phase transitions in TB's are controlled by electric, exchange fields and circularly polarized light. As a result, we find that by applying electric and exchange fields, four groups of spin-valley currents are perfectly filtered, directly induced by topological phase transitions. Control of currents, carried by single, double and triple channels of spin-valley electrons in silicene junction, may be achievable by adjusting magnitudes of electric, exchange fields and circularly polarized light. We may identify that the key factor behind the spin-valley current filtered at the transition points may be due to zero and non-zero Chern numbers. Electrons that are allowed to transport at the transition points must obey zero-Chern number which is equivalent to zero mass and zero-Berry's curvature, while electrons with non-zero Chern number are perfectly suppressed. Very large magnetoresistance dips are found directly induced by topological phase transition points. Our study also discusses the effect of spin-valley dependent Hall conductivity at the transition points on ballistic transport and reveals the potential of silicene as a topological material for spin-valleytronics.

中文翻译：

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由硅烯中的拓扑相变引起的大磁阻下降和完美的自旋谷滤波器

摘要 研究了基于硅烯的 N/TB/N/TB/N 结中的自旋谷输运和磁阻，其中 N 和 TB 是正常的硅烯和拓扑势垒。TB 中的拓扑相变由电场、交换场和圆偏振光控制。结果，我们发现通过施加电场和交换场，四组自旋谷电流被完美地过滤，直接由拓扑相变引起。控制由硅烯结中自旋谷电子的单通道、双通道和三通道携带的电流，可以通过调节电场、交换场和圆偏振光的大小来实现。我们可以确定在过渡点过滤的自旋谷电流背后的关键因素可能是由于零和非零陈数。允许在过渡点传输的电子必须服从零陈数，这相当于零质量和零贝瑞曲率，而具有非零陈数的电子则被完全抑制。发现由拓扑相变点直接引起的非常大的磁阻下降。我们的研究还讨论了自旋谷相关霍尔电导率在过渡点对弹道传输的影响，并揭示了硅烯作为自旋谷电子学拓扑材料的潜力。