Smart and Emerging Materials

While it has been recently demonstrated that, for quasi-2D electron gas (Q2DEG) with one filled miniband, the dynamic exchange fx, fx and fh kernels cancel each other in the low-density regime rs tends to infinity (by half and completely, for the spin-neutral and fully spin-polarized cases, respectively) [1], here we analytically show that the same happens at arbitrary densities at short distances. This motivates us to study the confinement dependence of the excitations in Q2DEG.  Our calculations unambiguously confirm that, at strong confinements,  the time-dependent exact exchange excitation energies approach the single-particle Kohn-Sham ones for the spin-polarized case, while the same, but less pronounced, tendency is observed for spin-neutral Q2DEG [2].

Image:

Fig.1. Time-dependent exact exchange (TDEXX), Kohn-Sham (KS), and Random Phase Approximation (RPA) excitation energies of the fully spin-polarized quasi-2DEG of the density parameter , confined with the strictly 2D uniform positive charge of the density parameter . For better visualization, each point is presented relative to the arithmetic mean of the TDEXX, KS, and RPA values.

Recent publications

1. V. U. Nazarov (2017) Quasi-low-dimensional electron gas with one populated band as a testing ground for time-dependent density-functional theory of mesoscopic systems, Physical Review Letters 118:236802.

2. V. U. Nazarov (2016) Exact exact exchange potential of two- and one-dimensional electron gases beyond the asymptotic limit, Physical Review B 93:195432.

References

1. V. U. Nazarov (2017) Quasi-low-dimensional electron gas with one populated band as a testing ground for time-dependent density-functional theory of mesoscopic systems, Physical Review Letters 118:236802.

2.  V. U. Nazarov (2018) Crossover between collective and independent-particle excitations in quasi-2D electron gas with one filled miniband, arXiv:1802.07004 [cond-mat.mes-hall].