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Theory for electric dipole superconductivity with an application for bilayer excitons.

Jiang QD, Bao ZQ, Sun QF, Xie XC - Sci Rep (2015)

Bottom Line: However, experimental measurements only provide indirect evidence for the existence of exciton superfluid.In this article, by viewing the exciton in a bilayer system as an electric dipole, we derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors.By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect.

View Article: PubMed Central - PubMed

Affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, P.R. China.

ABSTRACT
Exciton superfluid is a macroscopic quantum phenomenon in which large quantities of excitons undergo the Bose-Einstein condensation. Recently, exciton superfluid has been widely studied in various bilayer systems. However, experimental measurements only provide indirect evidence for the existence of exciton superfluid. In this article, by viewing the exciton in a bilayer system as an electric dipole, we derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors. By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect. These effects can provide direct evidence for the formation of the exciton superfluid state in bilayer systems and pave new ways to drive an electric dipole current.

No MeSH data available.


Related in: MedlinePlus

Meissner-type effect of the electric dipole superconductor.(a) The schematic diagram of the device consisting of a cylindrical hollow conductor and a circular bilayer exciton system (the electric dipole superconductor), and (b) the cross section of the device. Rin (Rout) is the inner (outer) radius of the hollow conductor, and rout is the radius of the dipole superconductor. m is the middle plane of the bilayer exciton, and l is distance between dipole superconductor and the point Q where magnetic field can be measured. h and d are, respectively, the thickness of the conductor and the dipole superconductor and t is the distance between them. (c,d) The induced super dipole current Jp and the gradient of the induced magnetic field  in the middle plane m versus radius r. (e) The induced magnetic field  versus the distance l. The parameters are Rin = 1 mm, Rout = 1 cm, h = 1.5 cm, t = 0.1 mm, and rout = 1 mm, and the thickness d = 13 nm and d = 10 nm, respectively.
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f2: Meissner-type effect of the electric dipole superconductor.(a) The schematic diagram of the device consisting of a cylindrical hollow conductor and a circular bilayer exciton system (the electric dipole superconductor), and (b) the cross section of the device. Rin (Rout) is the inner (outer) radius of the hollow conductor, and rout is the radius of the dipole superconductor. m is the middle plane of the bilayer exciton, and l is distance between dipole superconductor and the point Q where magnetic field can be measured. h and d are, respectively, the thickness of the conductor and the dipole superconductor and t is the distance between them. (c,d) The induced super dipole current Jp and the gradient of the induced magnetic field in the middle plane m versus radius r. (e) The induced magnetic field versus the distance l. The parameters are Rin = 1 mm, Rout = 1 cm, h = 1.5 cm, t = 0.1 mm, and rout = 1 mm, and the thickness d = 13 nm and d = 10 nm, respectively.

Mentions: In the following, we use the London-type equations to analyse the Meissner-type effect. We begin by considering a two-dimensional circular electric dipole superconductor with a radius rout located in a non-uniform external magnetic field Bext created by a cylindrical hollow conductor with an inner (outer) radius Rin (Rout) and a height h (shown in Fig. 2a). The distance between the cylindrical hollow conductor and the dipole superconductor is t. Figure 2b depicts the cross-section of the device. A uniform electric current along the azimuthal direction in the hollow conductor creates a non-uniform magnetic field with a gradient (see Supplementary), which can induce a super dipole current in the electric dipole superconductor. Substitute into the London-type equation (3), considering the rotational symmetry of the whole device and ∇ ⋅ Jp = 0, we can obtain the super electric dipole current density Jp at radius r (flowing in the azimuthal direction):


Theory for electric dipole superconductivity with an application for bilayer excitons.

Jiang QD, Bao ZQ, Sun QF, Xie XC - Sci Rep (2015)

Meissner-type effect of the electric dipole superconductor.(a) The schematic diagram of the device consisting of a cylindrical hollow conductor and a circular bilayer exciton system (the electric dipole superconductor), and (b) the cross section of the device. Rin (Rout) is the inner (outer) radius of the hollow conductor, and rout is the radius of the dipole superconductor. m is the middle plane of the bilayer exciton, and l is distance between dipole superconductor and the point Q where magnetic field can be measured. h and d are, respectively, the thickness of the conductor and the dipole superconductor and t is the distance between them. (c,d) The induced super dipole current Jp and the gradient of the induced magnetic field  in the middle plane m versus radius r. (e) The induced magnetic field  versus the distance l. The parameters are Rin = 1 mm, Rout = 1 cm, h = 1.5 cm, t = 0.1 mm, and rout = 1 mm, and the thickness d = 13 nm and d = 10 nm, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495569&req=5

f2: Meissner-type effect of the electric dipole superconductor.(a) The schematic diagram of the device consisting of a cylindrical hollow conductor and a circular bilayer exciton system (the electric dipole superconductor), and (b) the cross section of the device. Rin (Rout) is the inner (outer) radius of the hollow conductor, and rout is the radius of the dipole superconductor. m is the middle plane of the bilayer exciton, and l is distance between dipole superconductor and the point Q where magnetic field can be measured. h and d are, respectively, the thickness of the conductor and the dipole superconductor and t is the distance between them. (c,d) The induced super dipole current Jp and the gradient of the induced magnetic field in the middle plane m versus radius r. (e) The induced magnetic field versus the distance l. The parameters are Rin = 1 mm, Rout = 1 cm, h = 1.5 cm, t = 0.1 mm, and rout = 1 mm, and the thickness d = 13 nm and d = 10 nm, respectively.
Mentions: In the following, we use the London-type equations to analyse the Meissner-type effect. We begin by considering a two-dimensional circular electric dipole superconductor with a radius rout located in a non-uniform external magnetic field Bext created by a cylindrical hollow conductor with an inner (outer) radius Rin (Rout) and a height h (shown in Fig. 2a). The distance between the cylindrical hollow conductor and the dipole superconductor is t. Figure 2b depicts the cross-section of the device. A uniform electric current along the azimuthal direction in the hollow conductor creates a non-uniform magnetic field with a gradient (see Supplementary), which can induce a super dipole current in the electric dipole superconductor. Substitute into the London-type equation (3), considering the rotational symmetry of the whole device and ∇ ⋅ Jp = 0, we can obtain the super electric dipole current density Jp at radius r (flowing in the azimuthal direction):

Bottom Line: However, experimental measurements only provide indirect evidence for the existence of exciton superfluid.In this article, by viewing the exciton in a bilayer system as an electric dipole, we derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors.By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect.

View Article: PubMed Central - PubMed

Affiliation: International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, P.R. China.

ABSTRACT
Exciton superfluid is a macroscopic quantum phenomenon in which large quantities of excitons undergo the Bose-Einstein condensation. Recently, exciton superfluid has been widely studied in various bilayer systems. However, experimental measurements only provide indirect evidence for the existence of exciton superfluid. In this article, by viewing the exciton in a bilayer system as an electric dipole, we derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors. By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect. These effects can provide direct evidence for the formation of the exciton superfluid state in bilayer systems and pave new ways to drive an electric dipole current.

No MeSH data available.


Related in: MedlinePlus