Magneto-transport and magnetocaloric properties of highly doped (Ga,Mn)As DMS confined systems

Abstract

Abstract This work investigates the magneto-transport and magnetocaloric properties of interacting holes in highly Mn-doped (Ga,Mn)As. The model includes hole–longitudinal optical phonon coupling and analyzes the effects of temperature (0–50 K) and magnetic field (−5 to 5 T). The energy spectrum is obtained from the Schrödinger equation, and thermodynamic properties are evaluated using Boltzmann–Gibbs statistics. The formalism and numerical calculation are applied to (Ga 0.97 Mn 0.03 As) containing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>3</mml:mn> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> Mn. The magnetic susceptibility behavior indicates that antiferromagnetic interactions are associated with ferromagnetic order in (Ga,Mn)As under certain conditions. Additionally, both the adiabatic temperature change <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>T</mml:mi> <mml:mrow> <mml:mi>ad</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> and the magnetic entropy change <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>S</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">M</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> </mml:math> are calculated. The minimum of magnetic entropy change ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mi>S</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">M</mml:mi> </mml:mrow> </mml:msub> <mml:mrow> <mml:mo>/</mml:mo> </mml:mrow> <mml:msub> <mml:mi>K</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">B</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> ) is found to increase linearly with applied magnetic field and provides −0.54 for the field value of 2 T. In addition, the persistent current in the presence of magnetic fields is also investigated considering the role of the hole–hole interactions. Our calculations highlight two interesting results: a substantial reduction in the current results from an increase in the magnetic field at low temperatures on the one hand, and on the other hand, the interaction between holes induces an increase in the overall amplitude of the current.