TY - JOUR

T1 - Diamagnetic persistent currents for electrons in ballistic billiards subject to a point flux

AU - Zelyak, Oleksandr

AU - Murthy, Ganpathy

PY - 2008/9/4

Y1 - 2008/9/4

N2 - We study the persistent current of noninteracting electrons subject to a pointlike magnetic flux in the simply connected chaotic Robnik-Berry quantum billiard and also in an annular analog thereof. For the simply connected billiard, we find a large diamagnetic contribution to the persistent current at small flux, which is independent of the flux and is proportional to the number of electrons (or equivalently the density since we keep the area fixed). The size of this diamagnetic contribution is much larger than mesoscopic fluctuations in the persistent current in the simply connected billiard. Moreover, it can ultimately be traced to the response of the angular-momentum l=0 levels (neglected in semiclassical expansions) on the unit disk to a pointlike flux at its center. The same behavior is observed for the annular billiard when the inner radius is much smaller than the outer one. The usual fluctuating persistent current and Anderson-like localization due to boundary scattering are seen when the annulus tends to a one-dimensional ring. We explore the conditions for the observability of this phenomenon.

AB - We study the persistent current of noninteracting electrons subject to a pointlike magnetic flux in the simply connected chaotic Robnik-Berry quantum billiard and also in an annular analog thereof. For the simply connected billiard, we find a large diamagnetic contribution to the persistent current at small flux, which is independent of the flux and is proportional to the number of electrons (or equivalently the density since we keep the area fixed). The size of this diamagnetic contribution is much larger than mesoscopic fluctuations in the persistent current in the simply connected billiard. Moreover, it can ultimately be traced to the response of the angular-momentum l=0 levels (neglected in semiclassical expansions) on the unit disk to a pointlike flux at its center. The same behavior is observed for the annular billiard when the inner radius is much smaller than the outer one. The usual fluctuating persistent current and Anderson-like localization due to boundary scattering are seen when the annulus tends to a one-dimensional ring. We explore the conditions for the observability of this phenomenon.

UR - http://www.scopus.com/inward/record.url?scp=51749112703&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=51749112703&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.78.125305

DO - 10.1103/PhysRevB.78.125305

M3 - Article

AN - SCOPUS:51749112703

SN - 1098-0121

VL - 78

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

IS - 12

M1 - 125305

ER -