Quantum Transport Properties of Two-Dimensional Quantum Lattices under Synthetic Magnetic

Motivated by recent experimental progress, we study the quantum transport properties of two-dimensional electron gases under high perpendicular magnetic fields. We use a simple tight-binding model to model the system and open-source software to simulate quantum electronic transport properties such as band structure variations and conductance-flux relationships in such systems. Dependence of quantum transport properties on two-dimensional square, triangular and kagome lattice shapes were studied adding a Gaussian noise to account for the impurities. Numerical simulations are presented to predict the emergence of physical effects related to quantum Hall effect, such as the existence of Landau levels and edge states. The kagome lattice exhibits a different band structure giving rise to a flat band, due to its trihexagonal geometry. The peak conductance value increases with decreasing lattice constant due to higher transmission probability. The transport properties vary significantly with lattice geometries, both with the lattice type and the lattice constant.

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Kagome van-der-Waals Pd3P2S8 with flat band

Scientific Reports ◽

10.1038/s41598-020-77825-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Seunghyun Park ◽

Soonmin Kang ◽

Haeri Kim ◽

Ki Hoon Lee ◽

Pilkwang Kim ◽

...

Keyword(s):

Diamagnetic Susceptibility ◽

Van Der Waals ◽

Localized States ◽

Flat Band ◽

Two Dimensional ◽

Kagome Lattice ◽

Kagomé Lattice ◽

Localized State ◽

Low Dimensional ◽

Important Structure

AbstractWith the advanced investigations into low-dimensional systems, it has become essential to find materials having interesting lattices that can be exfoliated down to monolayer. One particular important structure is a kagome lattice with its potentially diverse and vibrant physics. We report a van-der-Waals kagome lattice material, Pd3P2S8, with several unique properties such as an intriguing flat band. The flat band is shown to arise from a possible compact-localized state of all five 4d orbitals of Pd. The diamagnetic susceptibility is precisely measured to support the calculated susceptibility obtained from the band structure. We further demonstrate that Pd3P2S8 can be exfoliated down to monolayer, which ultimately will allow the possible control of the localized states in this two-dimensional kagome lattice using the electric field gating.

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Realization of flat band with possible nontrivial topology in electronic Kagome lattice

Science Advances ◽

10.1126/sciadv.aau4511 ◽

2018 ◽

Vol 4 (11) ◽

pp. eaau4511 ◽

Cited By ~ 29

Author(s):

Zhi Li ◽

Jincheng Zhuang ◽

Li Wang ◽

Haifeng Feng ◽

Qian Gao ◽

...

Keyword(s):

Quantum Interference ◽

Edge State ◽

Dimensional Structure ◽

Flat Band ◽

Destructive Interference ◽

Two Dimensional ◽

Kagome Lattice ◽

Experimental Realization ◽

Kagomé Lattice ◽

Nontrivial Topology

The energy dispersion of fermions or bosons vanishes in momentum space if destructive quantum interference occurs in a frustrated Kagome lattice with only nearest-neighbor hopping. A discrete flat band (FB) without any dispersion is consequently formed, promising the emergence of fractional quantum Hall states at high temperatures. Here, we report the experimental realization of an FB with possible nontrivial topology in an electronic Kagome lattice on twisted multilayer silicene. Because of the unique low-buckled two-dimensional structure of silicene, a robust electronic Kagome lattice has been successfully induced by moiré patterns after twisting the silicene multilayers. The electrons are localized in the Kagome lattice because of quantum destructive interference, and thus, their kinetic energy is quenched, which gives rise to an FB peak in the density of states. A robust and pronounced one-dimensional edge state has been revealed at the Kagome edge, which resides at higher energy than the FB. Our observations of the FB and the exotic edge state in electronic Kagome lattice open up the possibility that fractional Chern insulators could be realized in two-dimensional materials.

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First-principles design of a half-filled flat band of the kagome lattice in two-dimensional metal-organic frameworks

Physical Review B ◽

10.1103/physrevb.94.081102 ◽

2016 ◽

Vol 94 (8) ◽

Cited By ~ 35

Author(s):

Masahiko G. Yamada ◽

Tomohiro Soejima ◽

Naoto Tsuji ◽

Daisuke Hirai ◽

Mircea Dincă ◽

...

Keyword(s):

First Principles ◽

Metal Organic Frameworks ◽

Flat Band ◽

Two Dimensional ◽

Kagome Lattice ◽

Kagomé Lattice ◽

Metal Organic

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Enabling Large-Scale Simulations of Quantum Transport with Manycore Computing

Electronics ◽

10.3390/electronics10030253 ◽

2021 ◽

Vol 10 (3) ◽

pp. 253

Author(s):

Yosang Jeong ◽

Hoon Ryu

Keyword(s):

Quantum Transport ◽

Large Scale ◽

Performance Enhancement ◽

Silicon Nanowire ◽

Matrix Multiplication ◽

Tight Binding ◽

Optimization Techniques ◽

Wide Energy Range ◽

Processing Unit ◽

Binding Model

The non-equilibrium Green’s function (NEGF) is being utilized in the field of nanoscience to predict transport behaviors of electronic devices. This work explores how much performance improvement can be driven for quantum transport simulations with the aid of manycore computing, where the core numerical operation involves a recursive process of matrix multiplication. Major techniques adopted for performance enhancement are data restructuring, matrix tiling, thread scheduling, and offload computing, and we present technical details on how they are applied to optimize the performance of simulations in computing hardware, including Intel Xeon Phi Knights Landing (KNL) systems and NVIDIA general purpose graphic processing unit (GPU) devices. With a target structure of a silicon nanowire that consists of 100,000 atoms and is described with an atomistic tight-binding model, the effects of optimization techniques on the performance of simulations are rigorously tested in a KNL node equipped with two Quadro GV100 GPU devices, and we observe that computation is accelerated by a factor of up to ∼20 against the unoptimized case. The feasibility of handling large-scale workloads in a huge computing environment is also examined with nanowire simulations in a wide energy range, where good scalability is procured up to 2048 KNL nodes.

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