Transport theory and spin-transfer physics in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>d</mml:mi> </mml:math> -wave altermagnets
Ricardo Zarzuela, Rodrigo Jaeschke‐Ubiergo, Olena Gomonay, Libor Šmejkal, Jairo Sinova
Abstract
We develop a mesoscale transport theory for the charge and spin degrees of freedom of itinerant carriers in a $d$-wave altermagnet. Our effective Lagrangian description is built on the slave-boson formulation of the microscopic $t\ensuremath{-}J$ model. We obtain a spin-polarized diffusive contribution to the effective Hamiltonian, which has no counterpart in conventional antiferromagnetism and is parametrized by the spin splitting, responsible for the so-called spin-splitter effect in $d$-wave altermagnets. We also elucidate the spin-transfer response of the itinerant fluid as well as the spin pumping into the altermagnet, which exhibit previously unidentified combinations of the charge current and spatial partial derivatives (namely, {${j}_{x}^{e},{\ensuremath{\partial}}_{y}$} and {${j}_{y}^{e},{\ensuremath{\partial}}_{x}$}). The emergent spin-transfer physics in $d$-wave altermagnets opens up promising perspectives for the dynamics of spin textures, such as the domain-wall motion driven by transverse charge currents. Additionally, we consider the effect of elastic distortions on the aforementioned transport properties.