研究目的
Investigating the control of an electron-hole super?uid in semiconductor coupled quantum wells and double layers of a two-dimensional material by an external periodic ?eld.
研究成果
The study demonstrates the possibility to control the electron-hole super?uid in CQWs or double layers of a 2D material by applying an external periodic potential. The critical temperature of the electron-hole pairing is controlled by the electron-hole pairing parameter, the density of states, and the position of the Fermi energy. The results indicate a second-order phase transition between the super?uid and electron-hole plasma phases, which can be tuned by the external periodic potential.
研究不足
The study assumes that the order parameter does not depend on the momentum and that the dispersion relation is the same for electrons and holes. The phase ?uctuations of the order parameter and quantum ?uctuations are not included in the mean-?eld approach.
1：Experimental Design and Method Selection:
The study employs a mean-?eld approximation for the many-body system of electrons and holes, using the partition function of the grand-canonical ensemble at temperature T and the chemical potentials of the electrons and the holes. The free energy is minimized to define the mean-?eld solution with a nonvanishing order parameter of the super?uid phase.
2：Sample Selection and Data Sources:
The system of spatially separated electrons and holes is realized in semiconductor coupled quantum wells (CQWs) or double layers of a 2D material, with equal densities of electrons and holes to ensure neutrality.
3：List of Experimental Equipment and Materials:
The external periodic potential is created by gates periodically attached to the quantum wells or double layers of the 2D material, or by the moiré pattern of two twisted layers.
4：Experimental Procedures and Operational Workflow:
The dependence of the electron-hole pairing order parameter on the temperature, the charge carrier density, and the gate parameters is analyzed by minimizing the mean-?eld free energy.
5：Data Analysis Methods:
The second-order phase transition between super?uid and electron-hole plasma is analyzed for different parameters using a Landau expansion of the free energy.
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