Elastic and dynamical structural properties of La and Mn-doped SrTiO3 studied by neutron scattering and their relation with thermal conductivities

Abstract

The electron-doped SrTiO3 exhibits good thermoelectric properties, which makes this material a promising candidate of an n-type oxide thermoelectric device. Recent studies indicated that only a few percent co-doping of La and Mn in SrTiO3 substantially reduces the thermal conductivity, thereby greatly improving the thermoelectric figure of merit at room temperature. Our time-of-flight neutron scattering studies revealed that by doping both La and Mn into SrTiO3, the inelastic scattering spectrum shows a momentum-independent increase in the low-energy spectral weight approximately below 10 meV. The increase in the low-energy spectral weight exhibits a clear correlation with thermal conductivity. The correlation is attributed to dynamical and local structural fluctuations caused by the Jahn-Teller instability in Mn3+ ions coupled with the incipient ferroelectric nature of SrTiO3, as the origin of the low thermal conductivity.

Tuning the Electrical and Thermoelectric Properties of N Ion Implanted SrTiO3 Thin Films and Their Conduction Mechanisms

“…No significant change is observed since the concentration is very low. The bond length of pristine sample calculated from the Rietveld analysis is found to be in accordance with the literature 23 . It is observed that the bond lengths Ti-O in TiO 6 octahedra are almost constant after implantation (see Supplementary Information).…”

Sub-lattice of Jahn-Teller centers in hexaferrite crystal

“…Frequency dependence of such anomalies is given in explicit form by, e.g., Eq. 3[or (23), (24)]. It is completely defined by factor ωτ (ω is frequency of ultrasonic wave, τ is relaxation time).…”

“…The systems, where it can be observed, include single crystals [4][5][6][7] , thin films 8 , non-organic and organic molecules [9][10][11] , and even biomolecules [12][13][14][15] . The JTE approach is used for description of properties of functional materials, such as semiconductors [16][17][18] , magnetic materials 5,6,[19][20][21] , superconductors 22 , optical materials 10,18 , and multiferroics 4,17,23,24 . In crystals, the JTE can manifest itself local or uniform.…”

Evidence for a gapless Dirac spin-liquid ground state in a spin-3/2 triangular-lattice antiferromagnet

“…7(a)-7(c)]. The spectral weight of the continuum is mainly distributed at low momenta, thus largely excluding the phonon origin of the excitations [82]. The continuum centered around |Q| = 4π/(3a) becomes well cone-shaped below T f = 22 K [see Fig.…”