Enhancement of figure of merit for Nernst effect in Bi77Sb23 alloy by Te-doping
Enhancement of figure of merit for Nernst effect in Bi77Sb23 alloy by Te-doping
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DOI：
10.1063/5.0016205
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发表时间：
2020-09-08
影响因子：
4
通讯作者：
Yamamoto, Atsushi
中科院分区：
文献类型：
--
作者：
Murata, Masayuki;Nagase, Kazuo;Yamamoto, Atsushi
以Bi 77 Sb 23合金为研究对象，研究了载流子掺杂对能斯特效应品质因数z（Nernst）的影响，旨在提高室温下的无量纲品质因数z（Nernst）T.四种Bi 77 Sb 23合金-未掺杂、0.1-、0.2-和0.3-at.%碲掺杂-是由放电等离子烧结和退火。在10 K ~ 300 K温度范围内，在高达6 T的磁场中测量了未掺杂和掺Te的Bi_（77）Sb_（23）合金的能斯特热电势、电阻率和热导率，以确定z（能斯特）T。在300 K时，由于电子和空穴载流子迁移率的0.1-at.%的改变，能斯特热电势的幅度增加了102兴奋剂。此外，由于Te掺杂破坏了电荷中性，磁阻效应在整个温度范围内受到抑制，这有助于提高z（Nernst）T。由于增加的电子热导率，磁场中的热导率通过Te掺杂而增加。因此，由于0.1-at.%，Bi 77 Sb 23合金在300 K下的z（Nernst）T增加了329兴奋剂
The effect of carrier doping on the figure of merit for the Nernst effect z(Nernst) is investigated using Bi77Sb23 alloys, aiming at the enhancement of the dimensionless figure of merit z(Nernst)T at room temperature. Four Bi77Sb23 alloys-undoped, 0.1-, 0.2-, and 0.3-at.% Te-doped-are produced by spark plasma sintering and annealing. The Nernst thermopower, electrical resistivity, and thermal conductivity of undoped and Te-doped Bi77Sb23 alloys are measured in magnetic fields of up to 6T at temperatures from 10K to 300K to determine z(Nernst)T. The magnitude of the Nernst thermopower increases by 102% at 300K because of the modification of the electron and hole carrier mobility by 0.1-at.% Te-doping. In addition, the magnetoresistance effect is suppressed over the entire temperature range owing to the fact that charge neutrality is destroyed by Te-doping, and this contributes to the enhancement of z(Nernst)T. The thermal conductivity in the magnetic field is increased by Te-doping due to the increased electron thermal conductivity. Thus, z(Nernst)T for the Bi77Sb23 alloy at 300K is increased by 329% as a result of 0.1-at.% Te-doping.