Si. Shevchenko, VORTICES AND VORTICAL STRUCTURES IN SYSTEMS WITH PAIRING OF SPATIALLYSEPARATED ELECTRONS AND HOLES, Physical review. B, Condensed matter, 56(16), 1997, pp. 10355-10368
The properties of systems with pairing of spatially separated electron
s and holes are studied below the superconducting transition temperatu
re T-c. Another phenomenon in these systems is predicted. It is shown
that in certain nonuniform magnetic fields the planar vortices in whic
h the electron-hole pairs rotate as a whole in the plane of the struct
ure become energy advantageous. Although the planar vortices resemble
Onsager-Feynman and Abrikosov vortices, they must form a structure fun
damentally different from the one the above vortices form. This struct
ure is ordered but noninvariant under translation. In the absence of a
magnetic field planar vortices appear in the system due to thermal fl
uctuations. The velocity field of a planar vortex decreases inversely
with the distance to the vortex center. This leads to a pairing of the
rmally excited vortices with the opposite circulations at the temperat
ures below T-c.