Applied Physics Research; Vol. 9, No. 1; 2017 ISSN 1916-9639 E-ISSN 1916-9647 Published by Canadian Center of Science and Education 77 The Effects of Pressure and Temperature on the Magnetic Susceptibility of Semiconductor Quantum Dot in A Magnetic Field Faten BZOUR 1 , Mohammad K. ELSAID 1 & Ayham SHAER 1 1 Physics Department, Faculty of Science, An- Najah National University, Nablus, West Bank, Palestine Correspondence: Mohammad K. ELSAID, Physics Department, Faculty of Science, An- Najah National University, Nablus, West Bank, Palestine. E-mail: mkelsaid@najah.edu Received: November 25, 2016 Accepted: December 5, 2016 Online Published: January 2, 2017 doi:10.5539/apr.v9n1p77 URL: http://dx.doi.org/10.5539/apr.v9n1p77 Abstract In this work, we present a theoretical study of the magnetic susceptibility (χ ) of two-electron GaAs parabolic quantum dot (QD) under the combined effects of external pressure, temperature and magnetic field. We used the exact diagonalization method to obtain the eigenenergies by solving the two electron quantum dot Hamiltonian taking into account the dependence of the effective mass and dielectric constant on the hydrostatic pressure and temperature. The pressure and temperature show significant effects on the calculated QD spectra. Next, we investigate the behavior of the magnetization of a quantum dot as a function of external pressure, temperature, confining frequency and magnetic field. The singlet-triplet transitions in the ground state of the quantum dot spectra and the corresponding jumps in the magnetic susceptibility spectra have been shown. The comparison shows that our results are in very good agreement with the reported works. Keywords: Pressure; temperature; magnetic susceptibility; quantum dot, magnetic field; exact diagonalization 1. Introduction Recent nanofabrication methods have it possible to design different types of quantum dots with the flexibility of controlling the size, shape, and number of electrons. These controllable physical properties of the zero-dimensional nanostructure makes it promising candidate for a wide range of device applications like quantum dot lasers, solar cells, single electron transistors and quantum computers (Ashoori et al., 1993; Ciftja, 2013; Kastner, 1992; Loss & DiVincenzo, 1998; Burkard, Loss, & DiVincenzo, 1999). Different approaches had been used to solve the two interacting electrons QD- Hamiltonian, including the presence of an applied magnetic field, and had obtained the eigenenergies and eigenstates of the QD-system as a function of magnetic field strength (Wagner, Merkt, & Chaplik, 1992; Taut, 1994; Ciftja & Kumar, 2004; Kouwenhoven, Austing, & Tarucha, 2001; Sanjeev Kumar, Mukhopadhyay, & Chatterjee, 2016; Kandemir, 2005; El-Said, 1995; El-Said, 1998; El-Said, 2000; Elsaid, Al-Naafa, & Zugail, 2008; Maksym & Chakraborty, 1990; De Groote, Hornos, & Chaplik, 1992). The energy spectra shows spin-singlet (S) and spin-triplet (T) ground state oscillations. These spin oscillations show themselves as transition peaks in the spectra of magnetic and thermodynamic quantities like magnetization (ߊ), magnetic susceptibility (ᆗ) and heat capacity ( ܥ ௩ ) (Nguyen & Peeters, 2008; Nammas, Sandouqa, Ghassib, & Al-Sugheir, 2011; Boyacioglu & Chatterjee, 2012; Helle, Harju, & Nieminen, 2005; Schwarz et al., 2002; Räsänen et al., 2003; Climente, Planelles, & Movilla, 2004; Nguyen & Sarma, 2011; Rezaei & Kish, 2012; Dybalski & Hawrylak, 2005; Avetisyan, Chakraborty, & Pietiläinen, 2016). The aim of this work, is to investigate the magnetic susceptibility of two interacting electrons confined in a parabolic quantum dot which is presented in a magnetic field. The applied magnetic field is uniform and its direction is taken to be along z-axis that is perpendicular to the x-y plane of the QD. In addition, we consider the effects of the external pressure and temperature on the magnetic susceptibility curve. We initially applied the exact diagonalization method to solve the QD Hamiltonian and obtain the eigenenergies for various values of physical QD parameters. Secondly, we investigate the dependence of the QD magnetic susceptibility, as a thermodynamic quantity, on the pressure, temperature confining frequency and magnetic field strength. The rest of this paper is organized as follows: section II presents the Hamiltonian theory, computation diagonalization technique and the statistical thermodynamic relations of magnetic susceptibility for two