suppl. mat. for magnon wf law

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Suppl. Mat. for magnon WF law Kouki Nakata All the responsibilities rest with Kouki Nakata

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Suppl. Mat. for magnon WF law

Kouki Nakata

All the responsibilities rest with Kouki Nakata

K

Charge

Heat

Thermal Conductivity 𝑲 ≈ 𝑳𝟐𝟐 for Fermions

Seebeck & Peltier

WF law (Low temp.)

?

Electron = Fermion Magnon = Boson Textbook by Ashcroft & Mermin

Lorenz number =

= =

=

? ?

?

Magnon

Heat

Thermal Conductivity 𝑲 ≠ 𝑳𝟐𝟐 for Magnons Nakata, Simon, and Loss, Phys. Rev. B 92, 134425 (2015)

Seebeck & Peltier

WF law (Low temp.)

?

?

Electron = Fermion Magnon = Boson Textbook by Ashcroft & Mermin

Lorenz number =

= =

=

K

? ?

Magnon

Heat

Thermal Conductivity 𝑲 ≠ 𝑳𝟐𝟐 for Magnons Nakata, Simon, and Loss, Phys. Rev. B 92, 134425 (2015)

Textbook by Ashcroft & Mermin Eq. (13.56): K is measured under conditions of no quasi-particle current

①Magnons flow 𝐈m = −𝐿12𝜵𝑇 ②Magnon accumulation: Magnetization gradient 𝜵𝐵 ③Counter current 𝐈m = 𝐿11𝜵𝐵 ④A new quasi-equilibrium state 𝐈m = 0 in 𝜵𝐵∗: Measured

𝐈m = 𝐿11𝜵𝐵 − 𝐿12𝜵𝑇 = 0 𝜵𝐵∗ =𝐿12

𝐿11𝜵𝑇

!

𝐈𝑄 = 𝐿21𝜵𝐵∗ − 𝐿22𝜵𝑇 = −(𝐿22 − 𝐿21𝐿12/𝐿11)𝜵𝑇

Thermal conductivity 𝑲: 𝐈𝑄 ≡ −𝐾 ∙ 𝜵𝑇 with !

𝐈m = 0

K Note:

K

⓪Thermal gradient 𝜵𝑇