arXiv subjects

Bahniman Ghosh

Publications and source records attributed to Bahniman Ghosh.

22 records · Page 2Linked to original sources

arXiv2010

The role of electron-electron scattering in spin transport

We investigate spin transport in quasi 2DEG formed by III-V semiconductor heterojunctions using the Monte Carlo method. The results obtained with and without electron-electron scattering are compared and appreciable difference between the two is found. The electron-electron scattering leads to suppression of Dyakonov-Perel mechanism (DP) and enhancement of Elliott-Yafet mechanism (EY). Finally, spin transport in InSb and GaAs heterostructures is investigated considering both DP and EY mechanisms. While DP mechanism dominates spin decoherence in GaAs, EY mechanism is found to dominate in high mobility InSb. Our simulations predict a lower spin relaxation/decoherence rate in wide gap semiconductors which is desirable for spin transport.

cond-mat.mes-hall↗

arXiv2010

Spin relaxation due to electron-electron magnetic interaction in high Lande g-factor semiconductors

We investigate spin transport in InSb/InAlSb heterostructure using the Monte Carlo approach, generalized by including density matrix description of spin for taking spin dynamics into account. In addition to the dominant Dyakonov-Perel (DP) mechanism for spin control and relaxation, we consider magnetic interaction between electrons which assumes importance due to high electronic Lande g-factor in the material. It is found that while the effect of magnetic interaction is not important at low densities, it reduces the spin relaxation length by as much as 50% at higher densities. We also present a calculation which elucidates the suppression of decoherence attributed to wave vector dependent magnetic field in the DP relaxation mechanism. We note that magnetic interaction is a general relaxation mechanism which may assume importance in materials with high electronic Lande g-factor.

cond-mat.mes-hall↗

arXiv2001

Noncommutative X-Y model and Kosterlitz Thouless transition

Matrix models have been shown to be equivalent to noncommutative field theories. In this work we study noncommutative X-Y model and try to understand Kosterlitz Thouless transition in it by analysing the equivalent matrix model. We consider the cases of a finite lattice and infinite lattice separately. We show that the critical value of the matrix model coupling is identical for the finite and infinite lattice cases. However, the critical values of the coupling of the continuum field theory, in the large $ N $ limit, is finite in the infinite lattice case and zero in the case of finite lattice.

hep-th↗

arXiv1999

Killing Spinors and Supersymmetric AdS Orbifolds

We examine the behaviour of Killing spinors on AdS5 under various discrete symmetries of the spacetime. In this way we discover a number of supersymmetric orbifolds, reproducing the known ones and adding a few novel ones to the list. These orbifolds break the SO(4,2) invariance of AdS5 down to subgroups. We also make some comments on the non-compact Stiefel manifold W{4,2}.

hep-th↗