BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Field-controlled thermal spin transport in rutile-type altermagnet
 s
DTSTART;VALUE=DATE-TIME:20260924T140000Z
DTEND;VALUE=DATE-TIME:20260924T142000Z
DTSTAMP;VALUE=DATE-TIME:20260914T053245Z
UID:indico-contribution-553@indico.bitp.kiev.ua
DESCRIPTION:Speakers: Yuliia Gusieva (G.V. Kurdyumov Institute for Metal P
 hysics of the NAS of Ukraine)\nThe magnon-driven transport properties of a
  two-dimensional model of a $d$-wave altermagnet are investigated. As a ca
 se study\, we consider a rutile with easy-planar anisotropy (e.g.\, $\\mat
 hrm{NiF}_2$)\, where the sublattice magnetization vectors lie within the $
 xy$-plane in the equilibrium state. An external magnetic field is applied 
 perpendicular to this plane\, along the $z$-axis. The model Hamiltonian ac
 counts for anisotropy\, Zeeman interaction\, and the complex structure of 
 the Heisenberg exchange\, including ferromagnetic\, antiferromagnetic\, an
 d specific altermagnetic exchange contributions.\n\nWe computed the spectr
 um of spin waves and found that altermagnetism renders magnons chiral\, as
  in the case of the easy-planar $g$-wave altermagnets [1]. The altermagnet
 ically-induced magnon magnetic moment is $k$-dependent\, and its distribut
 ion over the 1st Brillouin zone possesses $d$-wave symmetry for each magno
 n branch. The latter results in a magnon-driven spin current in response t
 o an applied temperature gradient\, similar to that in easy-axial $d$-wave
  altermagnets [2]. The corresponding tensor of the thermal spin conductivi
 ty $\\sigma_{\\alpha\\beta}$ was derived from the transport Boltzmann equa
 tion within the relaxation time approximation. The direction of the spin c
 urrent is determined by the direction of the temperature gradient relative
  to the crystallographic axes (Fig. 1). An important finding of this resea
 rch is the possibility of controlling the spin conductivity by the applied
  magnetic field. We observe that at low temperatures\, the conductivity is
  governed by the lowest-energy magnon mode\, and its temperature dependenc
 e follows a $T^2$-law. However\, for high temperatures\, $\\sigma_{\\alpha
 \\beta}$ is temperature-independent\, and its value and sign are determine
 d by the magnetic field. The field-controlled spin conductivity highlights
  the potential for tunable magnonic and spin-caloritronic devices\, provid
 ing a robust mechanism for controlling spin and heat currents at the nanos
 cale.\n\n**Fig. 1.** Temperature dependencies of $\\sigma_{xy}$ for differ
 ent values of the reduced magnetic field $b = B_z / B_{\\mathrm{sf}}$\, wh
 ere $B_{\\mathrm{sf}}$ is the critical spin-flip field.\n\nThis work was s
 upported by the German Federal Ministry of Research\, Technology and Space
  (BMFTR) through the GU-QuMat project (01DK24008).\n\n[1] V.P. Kravchuk\, 
 et al.\, *Phys. Rev. B*\, **112**\, 144421 (2025).  \n[2] K.V. Yershov\, e
 t al.\, *Phys. Rev. B*\, **110**\, 144421 (2024).\n\nhttps://indico.bitp.k
 iev.ua/event/18/contributions/553/
LOCATION:Bogolyubov Institute for Theoretical Physics Conference Hall
URL:https://indico.bitp.kiev.ua/event/18/contributions/553/
END:VEVENT
END:VCALENDAR