Magnetic nature of the 500 meV peak in La
Sr
CuO
observed with resonant inelastic X-ray scattering at the Cu
-edge
銅K吸収端での共鳴非弾性X線散乱で観測されるLa
Sr
CuO
の500meVピークの磁気的性質
Ellis, D. S.*; Kim, J.*; Hill, J. P.*; 脇本 秀一
; Birgeneau, R. J.*; Shvyd'ko, Y.*; Casa, D.*; Gog, T.*; 石井 賢司; 池内 和彦*; Paramekanti, A.*; Kim, Y.-J.*
Ellis, D. S.*; Kim, J.*; Hill, J. P.*; Wakimoto, Shuichi; Birgeneau, R. J.*; Shvyd'ko, Y.*; Casa, D.*; Gog, T.*; Ishii, Kenji; Ikeuchi, Kazuhiko*; Paramekanti, A.*; Kim, Y.-J.*
We present a comprehensive study of the temperature and doping dependence of the 500 meV peak observed at
in resonant inelastic X-ray scattering (RIXS) experiments on La
CuO
. The intensity of this peak persists above the N
el temperature (
= 320 K), but decreases gradually with increasing temperature, reaching zero at around
= 500 K. The peak energy decreases with temperature in close quantitative accord with the behavior of the two-magnon
Raman peak in La
CuO
and, with suitable rescaling, agrees with the Raman peak shifts in EuBa
Cu
O
and K
NiF
. The overall dispersion of this excitation in the Brillouin zone is found to be in agreement with theoretical calculations for a two-magnon excitation. Upon doping, the peak intensity decreases analogous to the Raman mode intensity and appears to track the doping dependence of the spin-correlation length. Taken together, these observations strongly suggest that the 500 meV mode is magnetic in character and is likely a two-magnon excitation.