On non-monotonic temperature dependence of linear contact probability in atomic chains

Abstract

In this paper, we theoretically investigate the temperature T dependence of linear contact probability in atomic chains. In these chains, the transverse motion of the electrons is assumed to be confined in the harmonic oscillator confinement model. The intra-chain electron correlations are treated within both Hartree–Fock Approximation (HFA) and Random Phase Approximation (RPA). As artifact HFA correlation functions are used in the RPA perturbative calculations. Results are presented for numerically computed pair-correlation functions at different temperatures and electron densities. An enhanced singlet-state is observed in these chains at zero inter-electronic spacing which remains independent of T. At non zero inter-electronic spacing, shrinking of Pauli’s hole is observed with increasing T. Using the RPA, the short-range pair-correlation functions are found to be considerably modified at finite-T and contact probability shows non-monotonic dependence on T. Smearing of exchange-correlation hole is also observed above a critical value of T in the diffusion zone. We also estimate the strength of the coupling parameter up to what the RPA is capable of dealing with carrier correlations in atomic chains. This work may prove useful for density functional theory calculations as estimation of the exchange-correlation hole is imperative for exchange-correlation functionals.