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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

A side view of the exciton in bilayer system and the induced supercurrent by magnetic field gradient.(a) The top and bottom layers host holes and electrons respectively, and the middle blue block stands for the interlayer barrier which prevents tunneling between the two layers. (b) The left (right) panel shows the induced super electric dipole current for magnetic field gradient ∂Bz/∂z < 0 (∂Bz/∂z > 0). The arrows on the blue lines denote the direction of positive charge flow in each layer.
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f1: A side view of the exciton in bilayer system and the induced supercurrent by magnetic field gradient.(a) The top and bottom layers host holes and electrons respectively, and the middle blue block stands for the interlayer barrier which prevents tunneling between the two layers. (b) The left (right) panel shows the induced super electric dipole current for magnetic field gradient ∂Bz/∂z < 0 (∂Bz/∂z > 0). The arrows on the blue lines denote the direction of positive charge flow in each layer.

Mentions: Before any further discussion, we need first to point out the specificity of excitons in bilayer systems. Because the electrons and holes are separated in space and bound with each other by the Coulomb interaction, the exciton in a bilayer system can be seen as a charge neutral electric dipole (as shown in Fig. 1a). On the other hand, superconductivity has been one of the central subjects in physics. The superconductor state has several fascinating properties, such as zero resistance19, the Meissner effect20, the Josephson effect21, and so on, which have many applications nowadays22. It is now well known that the superconductor is the condensate superfluid state of the Cooper pairs23, which can be viewed as electric monopoles. In other words, the superconductor state is the electric monopole condensated superfluid state. Thus, it is natural to ask whether the electric dipole superfluid state possesses many similar fascinating properties, just like its counterpart, the electric monopole superfluid state.


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

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

A side view of the exciton in bilayer system and the induced supercurrent by magnetic field gradient.(a) The top and bottom layers host holes and electrons respectively, and the middle blue block stands for the interlayer barrier which prevents tunneling between the two layers. (b) The left (right) panel shows the induced super electric dipole current for magnetic field gradient ∂Bz/∂z < 0 (∂Bz/∂z > 0). The arrows on the blue lines denote the direction of positive charge flow in each layer.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: A side view of the exciton in bilayer system and the induced supercurrent by magnetic field gradient.(a) The top and bottom layers host holes and electrons respectively, and the middle blue block stands for the interlayer barrier which prevents tunneling between the two layers. (b) The left (right) panel shows the induced super electric dipole current for magnetic field gradient ∂Bz/∂z < 0 (∂Bz/∂z > 0). The arrows on the blue lines denote the direction of positive charge flow in each layer.
Mentions: Before any further discussion, we need first to point out the specificity of excitons in bilayer systems. Because the electrons and holes are separated in space and bound with each other by the Coulomb interaction, the exciton in a bilayer system can be seen as a charge neutral electric dipole (as shown in Fig. 1a). On the other hand, superconductivity has been one of the central subjects in physics. The superconductor state has several fascinating properties, such as zero resistance19, the Meissner effect20, the Josephson effect21, and so on, which have many applications nowadays22. It is now well known that the superconductor is the condensate superfluid state of the Cooper pairs23, which can be viewed as electric monopoles. In other words, the superconductor state is the electric monopole condensated superfluid state. Thus, it is natural to ask whether the electric dipole superfluid state possesses many similar fascinating properties, just like its counterpart, the electric monopole superfluid state.

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