TY - JOUR

T1 - Renormalization of Fermi velocity in a composite two dimensional electron gas

AU - Weger, M

AU - Burlachkov, L.

PY - 1993

Y1 - 1993

N2 - We calculate the self-energy Σ(k, ω) of an electron gas with a Coulomb interaction in a composite 2D system, consisting of metallic layers of thickness d ≳ a0, where a0 = ħ2∊1/me2 is the Bohr radius, separated by layers with a dielectric constant ∊2 and a lattice constant c perpendicular to the planes. The behavior of the electron gas is determined by the dimensionless parameters kFa0 and kFc ∊2/∊1. We find that when ∊2/∊1 is large (≈5 or more), the velocity v(k) becomes strongly k-dependent near kF, and v(kF) is enhanced by a factor of 5-10. This behavior is similar to the one found by Lindhard in 1954 for an unscreened electron gas; however here we take screening into account. The peak in v(k) is very sharp (δk/kF is a few percent) and becomes sharper as ∊2/∊1 increases.
This velocity renormalization has dramatic effects on the transport properties; the conductivity at low T increases like the square of the velocity renormalization and the resistivity due to elastic scattering becomes temperature dependent, increasing approximately linearly with T. For scattering by phonons, ρ ∝ T2.
Preliminary measurements suggest an increase in vk in YBCO very close to kF.

AB - We calculate the self-energy Σ(k, ω) of an electron gas with a Coulomb interaction in a composite 2D system, consisting of metallic layers of thickness d ≳ a0, where a0 = ħ2∊1/me2 is the Bohr radius, separated by layers with a dielectric constant ∊2 and a lattice constant c perpendicular to the planes. The behavior of the electron gas is determined by the dimensionless parameters kFa0 and kFc ∊2/∊1. We find that when ∊2/∊1 is large (≈5 or more), the velocity v(k) becomes strongly k-dependent near kF, and v(kF) is enhanced by a factor of 5-10. This behavior is similar to the one found by Lindhard in 1954 for an unscreened electron gas; however here we take screening into account. The peak in v(k) is very sharp (δk/kF is a few percent) and becomes sharper as ∊2/∊1 increases.
This velocity renormalization has dramatic effects on the transport properties; the conductivity at low T increases like the square of the velocity renormalization and the resistivity due to elastic scattering becomes temperature dependent, increasing approximately linearly with T. For scattering by phonons, ρ ∝ T2.
Preliminary measurements suggest an increase in vk in YBCO very close to kF.

UR - https://scholar.google.co.il/scholar?q=Renormalization+of+Fermi+velocity+in+a+composite+2D+electron+gas++&btnG=&hl=en&as_sdt=0%2C5

M3 - Article

SN - 0217-9792

VL - 7

SP - 87

EP - 94

JO - International Journal of Modern Physics B

JF - International Journal of Modern Physics B

IS - 01n03

ER -