Kubo-Bastin approach for the spin Hall conductivity of decorated graphene

A new decomposition of the Kubo-Bastin formula

The Smrcka-Streda version of Kubo's linear response formula is widely used in the literature to compute non-equilibrium transport properties of heterostructures. It is particularly useful for the evaluation of intrinsic transport properties associated with the Berry curvature of the Bloch states, such as anomalous and spin Hall currents as well as the damping-like component of the spin-orbit torque. Here, we demonstrate in a very general way that the widely used decomposition of the Kubo-Bastin formula introduced by Smrcka and Streda contains an overlap, which has lead to widespread confusion …

无需能量积分的库布-巴斯廷公式分解

An Energy Integration Free Kubo-Bastin Formula Decomposition

本文提出了一种无需数值能量积分的库布-巴斯廷公式分解方法，通过解析地处理通用周期系统，显著降低了计算成本并简化了输运系数的评估。

Spin Hall Effect and Origins of Nonlocal Resistance in Adatom-Decorated Graphene

Recent experiments reporting unexpectedly large spin Hall effect (SHE) in graphene decorated with adatoms have raised a fierce controversy. We apply numerically exact Kubo and Landauer- Buttiker formulas to realistic models of gold-decorated disordered graphene (including adatom clustering) to obtain the spin Hall conductivity and spin Hall angle, as well as the nonlocal resistance as a quantity accessible to experiments. Large spin Hall angles of 0.1 are obtained at zero-temperature, but their dependence on adatom clustering differs from the predictions of semiclassical transport theories. F…

Hall conductivity of Sierpinski carpet

We calculate the Hall conductivity of a Sierpinski carpet using Kubo-Bastin formula. The quantization of Hall conductivity disappears when we increase the depth of the fractal. The Hall conductivity is no more proportional to the Chern number. Nevertheless, these quantities behave in a similar way showing some reminiscence of a topological nature of the Hall conductivity. We also study numerically the bulk-edge correspondence and find that the edge states become less manifested when the depth of Sierpinski carpet is increased.

DC conductivity of twisted bilayer graphene: Angle-dependent transport properties and effects of disorder

The in-plane DC conductivity of twisted bilayer graphene (TBLG) is calculated using an expansion of the real-space Kubo-Bastin conductivity in terms of Chebyshev polynomials. We investigate within a tight-binding (TB) approach the transport properties as a function of rotation angle, applied perpendicular electric field and vacancy disorder. We find that for high-angle twists, the two layers are effectively decoupled, and the minimum conductivity at the Dirac point corresponds to double the value observed in monolayer graphene. This remains valid even in the presence of vacancies, hinting that…

统一Kubo和Keldysh方法用于费米海依赖的非平衡可观测量：应用于自旋霍尔电流和自旋轨道扭矩在自旋电子学中

Reconciling Kubo and Keldysh Approaches to Fermi-Sea-Dependent Nonequilibrium Observables: Application to Spin Hall Current and Spin-Orbit Torque in Spintronics

本文通过无限大石墨烯模型，证明Kubo和Keldysh方法在计算自旋霍尔电流和自旋轨道扭矩时的数值等价性，解决了两种方法在非平衡可观测量中的分歧。