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RESEARCH PRODUCT

Constraints of reduced density-matrix functional theory for the two-dimensional homogeneous electron gas

Esa RäsänenA. Putaja

subject

Physicsta114Strongly Correlated Electrons (cond-mat.str-el)Order (ring theory)FOS: Physical sciencesQuantum Hall effectCondensed Matter PhysicsUpper and lower boundsElectronic Optical and Magnetic MaterialsBase (group theory)Condensed Matter - Strongly Correlated ElectronsQuantum mechanicsFermi gasScalingEnergy (signal processing)Ansatz

description

Reduced density-matrix functional theory (RDMFT) has become an appealing alternative to density-functional theory to describe electronic properties of strongly correlated systems. Here we derive exact conditions for the suitability of RDMFT to describe the two-dimensional homogeneous electron gas, which is the base system for semiconductor quantum dots and quantum Hall devices, for example. Following the method of Cioslowski and Pernal [J. Chem. Phys. 111, 3396 (1999)] we focus on the properties of power functionals of the form $f(n,{n}^{\ensuremath{'}})={(n{n}^{\ensuremath{'}})}^{\ensuremath{\alpha}}$ for the scaling function in the exchange-correlation energy. We show that in order to have stable and analytic solutions, and for $f$ to satisfy the homogeneous scaling constraint, the power is restricted to $1/4\ensuremath{\leqslant}\ensuremath{\alpha}\ensuremath{\leqslant}3/4$. Applying a reasonable ansatz for the momentum distribution and the lower bound for the exchange-correlation energy tightens the physical regime further to $0.64\ensuremath{\lesssim}\ensuremath{\alpha}\ensuremath{\leqslant}0.75$.

10.1103/physrevb.84.035104http://arxiv.org/abs/1105.2473