Far-infrared absorption of acoustic and optical magnetoplasmons in double-layered quantum wires

The far-infrared response of two-layered quantum wires in a perpendicular magnetic field is calculated self-consistently within the Hartree random-phase approximation. It is demonstrated that the oscillator strength of the acoustic mode is strongly enhanced if the lateral confining potential in the two layers is different. In a perpendicular magnetic field it exhibits a splitting in the vicinity of $2{\omega }_c,$ where ${\omega }_c$ is the cyclotron frequency, similar to the well known Bernstein modes in single-layered quantum wires. For small interlayer distances the acoustic magnetoplasmon shows oscillations which are related to the magnetic depopulation of the one-dimensional subbands.