Quantum-transport simulations with the Wigner-function formalism: Failure of conventional boundary-condition schemes

Europhysics Letters

Volumn 74, Issue 6, 2006, Pages 1060-1066

  Taj, D ^a,c   Genovese, L ^a,b   Rossi, F ^a  

^a POLITECNICO DI TORINO   (Italy)

^b UNIVERSITY OF ROME TOR VERGATA   (Italy)

^c UNIVERSITY OF TURIN   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33745668195     PISSN: 02955075     EISSN: 12864854     Source Type: Journal    
DOI: 10.1209/epl/i2006-10047-3     Document Type: Article

References (24)

1. See, e.g., JACOBONI C. and LUGLI P., The Monte Carlo Method for Semiconductor Device Simulations (Springer, Wien) 1989.
2. SCHOLL E. (Editor), Theory of Transport Properties of Semiconductor Nanostructures (Chapman & Hall, London) 1998.
3. IOTTI R. C. and ROSSI F., Phys. Rev. Lett., 87 (2001) 146603.
4. See, e.g., FRENSLEY W. R., Rev. Mod. Phys., 62 (1990) 3 and references therein.
5. It is worth mentioning that an equivalent and alternative approach to the density-matrix formalism is provided by the nonequilibrium Green's function technique [6]. Following this approach, Lake, Datta, and co-workers have proposed an efficient quantum-transport simulation scheme for the study of open semiconductor devices [7].
6. See, e.g., HAUG H. and JAUHO A.-P., Quantum Kinetics in Transport and Optics of Semiconductors (Springer, Berlin) 1996.
7. See, e.g., LAKE R. and DATTA S., Phys. Rev. B, 45 (1992) 6670.
8. See, e.g., HAUG H. and KOCH S. W., Quantum Theory of the Optical and Electronic Properties of Semiconductors, 3rd edition (World Scientific, Singapore) 1994.
9. See, e.g., ROSSI F. and KUHN T., Rev. Mod. Phys., 74 (2002) and references therein.
10. ROSSI F. et al., Phys. Rev. Lett., 80 (1998) 3348.
11. FRENSLEY W. R., Phys. Rev. Lett., 57 (1986) 2853.
12. See, e.g., KLUKSDAHL N. C. et al., Phys. Rev. B, 39 (1989) 7720.
13. JENSEN K. L. and BUOT F. A., J. Appl. Phys., 65 (1989) 5248.
14. ZACCARIA R. P. and ROSSI F., Phys. Rev. B, 67 (2003) 113311.
15. See, e.g., PASCOLI M. et al., Phys. Rev. B, 58 (1998) 3503.
16. This approach is intrinsically able to overcome the standard approximations of the semiclassical scattering theory; however, due to the huge amount of computation required, its applicability is often limited to short time-scales and extremely simplified situations.
17. b(k)) through the potential superoperator V.
18. z dz′ ∫ dk′ ν(z′, k - k′)/v(k) a(z′, k′) = b(-z, k). (10)
19. Indeed, it is well known that a "good" Wigner function, i.e., obtained as the Weyl-Wigner transform of a density matrix, will never give rise to negative charge distributions.
20. We stress that this problem does not affect the iterative solution of eq. (4), since in this case the kinetic part of the dynamics is treated exactly.
21. It is worth mentioning that Frensley himself pointed out that different active-region/reservoir coupling schemes (i.e., non-symmetric vs. symmetric derivatives) may lead to different physical pictures, and may also potentially lead to negative charge distributions.
22. j-1) /2) spatial average.
23. PROIETTI ZACCARIA R. et al., Appl. Phys. Lett., 84 (2004) 139.
24. PROIETTI ZACCARIA R. et al., Phys. Rev. B, 70 (2004) 195311.