LUHLUH JAHAN | University of Hyderabad (original) (raw)

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Papers by LUHLUH JAHAN

Research paper thumbnail of Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

Scientific Reports, 2019

The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic a... more The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range ...

Research paper thumbnail of Ground state properties of an exciton in a GaAs quantum dot in the presence of an external magnetic field using 1/N expansion method

The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the p... more The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. 1/N expansion method and shifted 1/N expansion method are employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. We have also studied the excited states of the exciton in the quantum dot. We could see the probability of quantum dot lasers by tuning the quantum dot parameters.The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. 1/N expansion method and shifted 1/N expansion method are employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. We have also studied the excited states of the exciton in the quantum dot. We could see the probability of quantum dot lasers by tuning the quantum dot pa...

Research paper thumbnail of Magnetic field effect on the energy levels of an exciton in a GaAs quantum dot: Application for excitonic lasers

Scientific reports, Jan 22, 2018

The problem of an exciton trapped in a Gaussian quantum dot (QD) of GaAs is studied in both two a... more The problem of an exciton trapped in a Gaussian quantum dot (QD) of GaAs is studied in both two and three dimensions in the presence of an external magnetic field using the Ritz variational method, the 1/N expansion method and the shifted 1/N expansion method. The ground state energy and the binding energy of the exciton are obtained as a function of the quantum dot size, confinement strength and the magnetic field and compared with those available in the literature. While the variational method gives the upper bound to the ground state energy, the 1/N expansion method gives the lower bound. The results obtained from the shifted 1/N expansion method are shown to match very well with those obtained from the exact diagonalization technique. The variation of the exciton size and the oscillator strength of the exciton are also studied as a function of the size of the quantum dot. The excited states of the exciton are computed using the shifted 1/N expansion method and it is suggested th...

Research paper thumbnail of Effect of temperature on the single-particle ground-state energy of a polar quantum dot with Gaussian confinement

The temperature and size dependence of the ground-state energy of a polaron in a Gaussian quantum... more The temperature and size dependence of the ground-state energy of a polaron in a Gaussian quantum dot have been investigated by using a variational technique. It is found that the ground-state energy increases with increasing temperature and decreases with the size of the quantum dot. Also, it is found that the ground-state energy is larger for a three-dimensional quantum dot as compared to a two-dimensional dot.

Research paper thumbnail of Ground state energy of an exciton in a spherical quantum dot in the presence of an external magnetic field

The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the p... more The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. A variational method is employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. It is also shown that the variation of the size of the exciton with the radius of the quantum dot.

Research paper thumbnail of Effect of temperature on the single-particle ground-state and self energy of a polar quantum dot with Gaussian confinement

The temperature dependence of the properties of a polaron in a Gaussian quantum dot has been inve... more The temperature dependence of the properties of a polaron in a Gaussian quantum dot has been investigated by using Lee-Low-Pines-Hybrechts variational technique and quantum statistical mechanics. It is shown that the ground-state energy increases with increasing temperature and the corresponding polaronic correction decreases. It is thus shown that for entire range of the coupling constant, polaronic effects decrease with increasing temperature.

Research paper thumbnail of Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

Scientific Reports, 2019

The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic a... more The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range ...

Research paper thumbnail of Ground state properties of an exciton in a GaAs quantum dot in the presence of an external magnetic field using 1/N expansion method

The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the p... more The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. 1/N expansion method and shifted 1/N expansion method are employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. We have also studied the excited states of the exciton in the quantum dot. We could see the probability of quantum dot lasers by tuning the quantum dot parameters.The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. 1/N expansion method and shifted 1/N expansion method are employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. We have also studied the excited states of the exciton in the quantum dot. We could see the probability of quantum dot lasers by tuning the quantum dot pa...

Research paper thumbnail of Magnetic field effect on the energy levels of an exciton in a GaAs quantum dot: Application for excitonic lasers

Scientific reports, Jan 22, 2018

The problem of an exciton trapped in a Gaussian quantum dot (QD) of GaAs is studied in both two a... more The problem of an exciton trapped in a Gaussian quantum dot (QD) of GaAs is studied in both two and three dimensions in the presence of an external magnetic field using the Ritz variational method, the 1/N expansion method and the shifted 1/N expansion method. The ground state energy and the binding energy of the exciton are obtained as a function of the quantum dot size, confinement strength and the magnetic field and compared with those available in the literature. While the variational method gives the upper bound to the ground state energy, the 1/N expansion method gives the lower bound. The results obtained from the shifted 1/N expansion method are shown to match very well with those obtained from the exact diagonalization technique. The variation of the exciton size and the oscillator strength of the exciton are also studied as a function of the size of the quantum dot. The excited states of the exciton are computed using the shifted 1/N expansion method and it is suggested th...

Research paper thumbnail of Effect of temperature on the single-particle ground-state energy of a polar quantum dot with Gaussian confinement

The temperature and size dependence of the ground-state energy of a polaron in a Gaussian quantum... more The temperature and size dependence of the ground-state energy of a polaron in a Gaussian quantum dot have been investigated by using a variational technique. It is found that the ground-state energy increases with increasing temperature and decreases with the size of the quantum dot. Also, it is found that the ground-state energy is larger for a three-dimensional quantum dot as compared to a two-dimensional dot.

Research paper thumbnail of Ground state energy of an exciton in a spherical quantum dot in the presence of an external magnetic field

The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the p... more The problem of an exciton trapped in a three dimensional Gaussian quantum dot is studied in the presence of an external magnetic field. A variational method is employed to obtain the ground state energy of the exciton as a function of the quantum dot size, the confinement strength and the magnetic field. It is also shown that the variation of the size of the exciton with the radius of the quantum dot.

Research paper thumbnail of Effect of temperature on the single-particle ground-state and self energy of a polar quantum dot with Gaussian confinement

The temperature dependence of the properties of a polaron in a Gaussian quantum dot has been inve... more The temperature dependence of the properties of a polaron in a Gaussian quantum dot has been investigated by using Lee-Low-Pines-Hybrechts variational technique and quantum statistical mechanics. It is shown that the ground-state energy increases with increasing temperature and the corresponding polaronic correction decreases. It is thus shown that for entire range of the coupling constant, polaronic effects decrease with increasing temperature.

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