Тип публикации: статья из журнала
Год издания: 2025
Идентификатор DOI: 10.1088/1361-6668/adc8dd
Аннотация: <jats:title>Abstract</jats:title> <jats:p>To study the thermodynamic properties of the disorder-induced transition between <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msub> Показать полностью</mml:mrow> </mml:math> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> superconducting gap functions, we calculate the grand thermodynamic potential Ω in the normal and the superconducting states. An expression for the difference between the two, Δ<jats:italic>Ω</jats:italic>, is derived for a two-band model for Fe-based systems with nonmagnetic impurities. The disorder is considered in a <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mi class="MJX-tex-calligraphic">T</mml:mi> </mml:mrow> </mml:mrow> </mml:math> </jats:inline-formula>-matrix approximation within the multiband Eliashberg theory. In the vicinity of the Born limit near the <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula>-to-<jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> transition, we find two solutions obtained for opposite directions of the system’s evolution with respect to the impurity scattering rate. By calculating the change in entropy Δ<jats:italic>S</jats:italic> and the change in the electronic specific heat Δ<jats:italic>C</jats:italic> from Δ<jats:italic>Ω</jats:italic>, we show that such a hysteresis is not due to the time-reversal symmetry breaking state, but that it instead points to the first order phase transition (PT) induced by the nonmagnetic disorder. Based on the Δ<jats:italic>Ω</jats:italic> calculations, a phase diagram is plotted representing the energetically favorable <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> states and the transition between them. At finite temperature, a first order PT line there is limited by a critical end point. Above that point, the sharp <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msub> <mml:mo accent="false" stretchy="false">→</mml:mo> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> transition transforms into a crossover between <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>±</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> and <jats:inline-formula> <jats:tex-math/> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> <mml:mo>+</mml:mo> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> </jats:inline-formula> states.</jats:p>
Журнал: Superconductor Science and Technology
Выпуск журнала: Т. 38, № 5
Номера страниц: 055002
ISSN журнала: 09532048
Издатель: Institute of Physics and IOP Publishing Limited