TY - JOUR

T1 - Numerical simulation of diffusive conductivity in Rashba split two-dimensional gas

AU - Itoh, Hiroyoshi

AU - Yamamoto, Kohji

AU - Inoue, Jun Ichiro

AU - Bauer, Gerrit E.W.

N1 - Funding Information:
The authors wish to thank S. Murakami and B. K. Nikolić for valuable discussions. This work was supported by the NEDO international project “Nano-scale Magnetoelectronics”, FEMD-CREST, Grants-in-Aid for Scientific Research (C) and for Scientific Research in Priority Areas “Semiconductor Nanospintronics” of The Ministry of Education, Culture, Sports, Science, and Technology of Japan, NAREGI Nanoscience Project, and the 21st Century COE Program “Frontiers of Computational Science”. A part of the numerical simulation was carried out on NanoGrid Computing system at Institute for Molecular Science, Okazaki.

PY - 2005/12

Y1 - 2005/12

N2 - We numerically model the conductivity of a two-dimensional electron gas (2DEG) in the presence of the Rashba spin-orbit (SO) interaction in the diffusive transport regime. We performed simulation using samples which width W and length L are up to 200 and 30 000, respectively, on a tight-binding square lattice. When the system is in the diffusive regime, the quadratic increase of the conductivity with SO interaction strength λSO derived previously by Born approximation is reproduced except for very weak SO interaction. In order to obtain satisfactory agreement between numerical and analytical results, the sample width and length should be much larger than the mean free path ℓ but the length should be shorter than the localization length ξ, e.g. 4ℓ≲W and 10ℓ≲L<ξ. The anomaly at weak SO interaction is also observed in the conductance fluctuation and the localization length, and is attributed to the finite size crossover from symplectic to orthogonal class with decreasing SO interaction. The typical values of the SO interaction characterizing the crossover obtained for ℓ∼48 are λSO∼1.0/W and 0.2/W when we impose open and periodic boundary conditions, respectively.

AB - We numerically model the conductivity of a two-dimensional electron gas (2DEG) in the presence of the Rashba spin-orbit (SO) interaction in the diffusive transport regime. We performed simulation using samples which width W and length L are up to 200 and 30 000, respectively, on a tight-binding square lattice. When the system is in the diffusive regime, the quadratic increase of the conductivity with SO interaction strength λSO derived previously by Born approximation is reproduced except for very weak SO interaction. In order to obtain satisfactory agreement between numerical and analytical results, the sample width and length should be much larger than the mean free path ℓ but the length should be shorter than the localization length ξ, e.g. 4ℓ≲W and 10ℓ≲L<ξ. The anomaly at weak SO interaction is also observed in the conductance fluctuation and the localization length, and is attributed to the finite size crossover from symplectic to orthogonal class with decreasing SO interaction. The typical values of the SO interaction characterizing the crossover obtained for ℓ∼48 are λSO∼1.0/W and 0.2/W when we impose open and periodic boundary conditions, respectively.

KW - Diffusive conductivity

KW - Numerical simulation

KW - Rashba spin-orbit interaction

KW - Universality class

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U2 - 10.1016/j.physe.2005.08.008

DO - 10.1016/j.physe.2005.08.008

M3 - Article

AN - SCOPUS:27744485120

VL - 30

SP - 120

EP - 125

JO - Physica E: Low-Dimensional Systems and Nanostructures

JF - Physica E: Low-Dimensional Systems and Nanostructures

SN - 1386-9477

IS - 1-2

ER -