Jahan K Luhluh, Boyacioglu Bahadir, Chatterjee Ashok
School of Physics, University of Hyderabad, Hyderabad, 500 046, India.
Vocational School of Health Services, Ankara University, 06290, Kecioren, Ankara, Turkey.
Sci Rep. 2019 Nov 1;9(1):15824. doi: 10.1038/s41598-019-52190-w.
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 of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.
使用具有陡度参数p的幂指数势模型，研究了限制势的形状对GaAs量子点的电子、热力学、磁性和输运性质的影响。在低温下，采用正则系综方法计算了平均能量、热容、磁化率和持续电流。结果表明，对于软限制，平均能量强烈依赖于p，而对于硬限制，它几乎与p无关。发现在低温和所考虑的磁场下，热容与限制势的形状和深度无关。结果表明，系统在临界磁场值处经历顺磁 - 抗磁转变。此外还表明，对于低势阱深度值，如果磁场超过某个值，无论势的形状如何，系统总是抗磁性的。在一定范围的磁场中，存在一个p值窗口，在其中可能会出现重新进入抗磁相的行为。最后，结果表明，当前量子点中的持续电流本质上是抗磁性的，其大小随点势的深度增加而增加，但在所考虑的参数下与p无关。
