Zr doped β-rhombohedral boron: Widely variable Seebeck coefficient and structural properties

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• 作者：Oksana Sologub^a ; ^b ; ^{oksana.sologub@univie.ac.at" class="auth_mail" title="E-mail the corresponding author} ; Leonid Salamakha^b ; Berthold Stö ; ger^c ; Yuichi Michiue^a ; Takao Mori^a ; ^{Mori.Takao@nims.go.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：β-rhombohedral boron ; Zr-doping ; p/n transition
• 刊名：Acta Materialia
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：122
• 期：Complete
• 页码：378-385
• 全文大小：1997 K

文摘

The doping effect of zirconium on the structure, Seebeck coefficient and electrical resistivity of β-rhombohedral B was studied for the metal rich concentration range Zr_xB_100−x, 1.88 ≤ x ≤ 2.75. Structural studies proved the Zr atoms mainly in E and D voids for the metal rich compositions, and also elucidated the minor Zr occupancies of the N, F and A₁ holes. Seebeck coefficients were effectively shifted within a wide range of positive and negative values by varying the Zr content (p-type: S_max ∼ +420 μVK⁻¹ at 673 K for x = 1.88; n-type: S_max ∼ −670 μVK⁻¹ at 473 K for x = 2.74). Electrical resistivities generally followed the Mott's relation for the variable-range hopping. Excellent compositional agreement has been observed between structural and thermoelectric properties discontinuities.