PT Journal
AU Varyukhin, SV
   Zakharov, AA
   Gershenzon, EM
   Gol'tsman, GN
   Ptitsyna, NG
   Chulkova, GM
TI AC losses and submillimeter absorption in single crystals La2CuO4
SO Phys. B Condens. Mat.
JI Phys. B Condens. Mat.
PY 1990
BP 1269
EP 1270
VL 165-166
DI 10.1016/S0921-4526(09)80220-2
DE metal-dielectric-La2Cu04
AB The La2CuO4 single crystals were used to carry out the measurements of transmission spectra within the submillimeter range of wavelengths, as well as the capacitance C and conductivity G in the region of acoustic frequencies of the metal-dielectric-La2Cu04 system at low temperatures. The optical spectra display a threshold character. There takes place a sharp decreasing of transmission signal in the energy range of hυ>1.5meV. The C(ω,T) and G(ω,T) dependences have a universal form characteristic of relaxation processes of the Debye type. The relaxation time dependence displays a thermoactivation character τ(T)-exp(ξ/T) with a gap value of ξ≃2meV,coinciding with the optical one. It is assumed that there exist excitations with a characteristic energy ~ 2meV in La2Cu04.A possible nature of the revealed low-energy excitations is discussed.
ER