Chebyshev polynomial method to Landauer–Büttiker formula of quantum transport in nanostructures

Yu, Yan; Zhang, Yan-Yang; Liu, Lei; Wang, Sisi; Guan, Ji-Huan; Xia, Yang; Li, Shu-Shen

doi:10.1063/5.0007682

Cited by 4 publications

(2 citation statements)

References 64 publications

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“…As an application, we studied mesoscopic TBG devices with a focus on small twist-angle systems and the transport signatures of lowdispersion energy bands in the vicinity of the CNP. This is one of the first applications of the spectral method to the Landauer transmission problem [68,69] and the first, to our knowledge, to formulate a direct expansion of the twoterminal conductance in terms of Chebyshev polynomials. The use of complex absorbing potentials, and associated modified Chebyshev polynomials, has allowed us to alleviate the computational cost of simulating (large) leads that behave as proper electron reservoirs.…”

Section: Discussionmentioning

confidence: 99%

Efficient Chebyshev polynomial approach to quantum conductance calculations: Application to twisted bilayer graphene

2023

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In recent years, Chebyshev polynomial expansions of tight-binding Green's functions have been successfully applied to the study of a wide range of spectral and transport properties of materials. However, the application of the Chebyshev approach to the study of quantum transport properties of noninteracting mesoscopic systems with leads has been hampered by the lack of a suitable Chebyshev expansion of Landaeur's formula or one of its equivalent formulations in terms of Green's functions in Keldysh's perturbation theory. Here, we tackle this issue by means of a hybrid approach that combines the efficiency of Chebyshev expansions with the convenience of complex absorbing potentials to calculate the conductance of two-terminal devices in a computationally expedient and accurate fashion. The versatility of the approach is demonstrated for mesoscopic twisted bilayer graphene (TBG) devices with up to 2.3 × 10 6 atomic sites. Our results highlight the importance of moiré effects, interlayer scattering events, and twist-angle disorder in determining the conductance curves in devices with a small twist angle near the TBG magic angle θ m ≈ 1.1 • .

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Section: Discussionmentioning

confidence: 99%

Efficient Chebyshev polynomial approach to quantum conductance calculations: Application to twisted bilayer graphene

2023

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“…This approach using the Chebyshev polynomial expansion, allows to include in a variety of imperfections, [39][40][41] and has been implemented in phonon systems, but not extensively been utilized particularly for magnon systems. It avoids inverting large matrices and belongs to the so-called kernel polynomial method (KPM) in a broader perspective [42][43][44][45]. Despite the fact that large computational resources are required, the high-performance computers and parallelization can greatly reduce the computational time, making the practical calculations feasible [46,47].…”

Section: Introductionmentioning

confidence: 99%

Real-space calculation of thermal Hall effects in strained and disordered kagome ferromagnets

Zhang,

2024

J. Phys. D: Appl. Phys.

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Ferromagnetic insulators may exhibit magnon Hall eﬀects when subjected to a temperature gradient due to the Dzyaloshinsky-Moriya interaction. In this study, we investigate the magnon thermal Hall conductivity κxy of kagome ferromagnets in real space using the kernel polynomial method. We ﬁrst establish the formalism in real space within the framework of linear response theory, which enables eﬃcient numerical calculations of thermal transport properties under various imperfections. The validity and accuracy of the real-space approach are conﬁrmed by comparing the calculations with those obtained in momentum space. This approach is particularly advantageous for computing the thermal transport coeﬃcients of disordered lattices. We consider two types of disorder in kagome ferromagnets and observe that both types signiﬁcantly inﬂuence κxy across the entire temperature range. This is in contrast to the eﬀects of strains, where strains primarily impact the maximum values of κxy.

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The first-principles study on electronic transport mechanism in palladium decorated graphene for inert gas sensing

khadim,

Majid,

Batool

et al. 2024

Opt Quant Electron

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Inert gases, despite various uses and industrial applications, may cause asphyxiation, so their detection and monitoring are essentially needed. However, the preparation of inert gas sensors is challenging due to the inactive chemical nature of these gases. This work was carried out to investigate the transport properties of inert gas sensors based on palladium-clusters-decoratedgraphene-sheets (Pd-Gr) using Density Functional Theory (DFT) based methodology. The sensors comprising Pd clusters Pdn (n = 2-5) decorated graphene were simulated to investigate the structural stability, adsorption, sensitivity, and electronic characteristics. The transport properties were studied using current-voltage (I-V) curves obtained via non-equilibrium Green's function (NEGF). The current appeared small at the start due to higher electrical resistance caused by charge transfer due to the adsorption of inert gases on the sensors. However, a voltage-dependent increase in the current took place afterward. The values of the resistance are found sensitive to the adsorption of the inert gases onto the sensors which helped to detect the gases. The energy difference of frontier molecular orbitals contributing to the conduction exhibited different responsive voltages which helped to points to the gas being adsorbed on the sensor. The findings of the work revealed that Pd2 sensors are sensitive towards xenon and neon, Pd3 and Pd4 are suitable for the detection of krypton and helium respectively whereas the Pd5 sensor is more appropriate for sensing argon and radon gases.

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Chebyshev polynomial method to Landauer–Büttiker formula of quantum transport in nanostructures

Cited by 4 publications

References 64 publications

Efficient Chebyshev polynomial approach to quantum conductance calculations: Application to twisted bilayer graphene

Efficient Chebyshev polynomial approach to quantum conductance calculations: Application to twisted bilayer graphene

Real-space calculation of thermal Hall effects in strained and disordered kagome ferromagnets

The first-principles study on electronic transport mechanism in palladium decorated graphene for inert gas sensing

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