Thermoelectric response in the incoherent transport region near Mott transition; The Case study of LaSrVO

モット転移近傍でのインコヒーレント輸送領域における熱電応答; LaSrVOに関する研究

打田 正輝*; 大石 晃史*; 松尾 まり; 小椎八重 航*; 小野瀬 佳文*; 森 道康  ; 藤岡 淳*; 宮坂 茂樹*; 前川 禎通; 十倉 好紀*

Uchida, Masaki*; Oishi, Koji*; Matsuo, Mari; Koshibae, Wataru*; Onose, Yoshinori*; Mori, Michiyasu; Fujioka, Jun*; Miyasaka, Shigeki*; Maekawa, Sadamichi; Tokura, Yoshinori*

We report a systematic investigation on the high-temperature thermoelectric response in a typical filling-control Mott transition system LaSrVO. In the vicinity of the Mott transition, incoherent charge transport appears with increasing temperature and the thermopower undergoes two essential crossovers, asymptotically approaching the limit values expected from the entropy consideration, as known as Heikes formula. By comparison with the results of the dynamical mean field theory, we show that the thermopower in the Mott critical state mainly measures the entropy per charge carrier that depends on electronic degrees of freedom available at the measurement temperature. Our findings verify that the Heikes formula is indeed applicable to the real correlated electron systems at practical temperatures (T200K).