2016/01/31 by Raphael Richter, Denitsa Shopova, Wenjie Xie +2
Materials Science · Physics and Astronomy · #Advanced Thermoelectric Materials and Devices #Doping #Fermi energy #Fermi level #Function (biology) #Heusler alloys: electronic and magnetic properties #Seebeck coefficient #Spectral function #Thermal Expansion and Ionic Conductivity #Thermoelectric effect #Thermoelectric materials #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1155/2018/9725321
published as Adv. Cond. Mat. Phys. 2018, 9725321 (2018) · 4 pages, 3 figures, revised version, additional data
openalex created_date 2016/06/24 · arxiv created 2016/09/22 · openalex publication_date 2018/01/01 · arxiv updated 2018/04/25 · openalex updated_date 2026/08/05
The sodium cobaltate system <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi><mml:mi mathvariant="normal">a</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>Co<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn mathvariant="normal">2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math> is a prominent representant of strongly correlated materials with promising thermoelectric response. In a combined theoretical and experimental study we show that, by doping the Co site of the compound at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>x</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.7</mml:mn></mml:math> with iron, a further increase of the Seebeck coefficient is achieved. The Fe defects give rise to effective hole doping in the high-thermopower region of larger sodium content <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:math>. Originally filled hole pockets in the angular-resolved spectral function of the material shift to low energy when introducing Fe, leading to a multisheet interacting Fermi surface. Because of the higher sensitivity of correlated materials to doping, introducing adequate substitutional defects is thus a promising route to manipulate their thermopower.