Quantum interference in nanometric devices: Ballistic transport across arrays of T-shaped quantum wires

We propose that recently realized T-shaped semiconductor quantum wires (T wires) could be exploited as three-terminal quantum interference devices. T wires are formed by intersecting two quantum wells (QWs). By use of a scattering matrix approach and Landauer-Buttiker theory, we calculate the conductance for ballistic transport in the parent QWs and across the wire region as a function of the injection energy. We show that different conductance profiles can be selected by tailoring the widths of the QWs and/or by combining more wires on the scale of the Fermi wavelength. Finally, we discuss the possibility of obtaining spin-dependent conductance of ballistic holes in the same structures.