Electrical Conduction Mechanism of β-MnTe Thin Film with Wurtzite-Type Structure Using Radiofrequency Magnetron Sputtering
Electrical Conduction Mechanism of β-MnTe Thin Film with Wurtzite-Type Structure Using Radiofrequency Magnetron Sputtering
复制标题
射频磁控溅射纤锌矿型β-MnTe薄膜的导电机制
DOI：
10.1002/pssr.202100641
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Yuji Sutou
中科院分区：
文献类型：
--
作者：
Mihyeon Kim;Shunsuke Mori;Yi Shuang;Shogo Hatayama;Daisuke Ando;Yuji Sutou
碲化锰（MnTe）化合物已知是多晶型硫属化物。最近，据报道，MnTe显示出非易失性存储器特性，其中电阻经由NiAs型（NC）结构（低电阻）和纤锌矿型（WZ）结构（高电阻）之间的多晶型转变而显著变化。这种结晶多晶型MnTe有望实现具有快速操作速度和超低操作能量的相变存储器。虽然NC‐MnTe，通常称为α‐MnTe，被深入研究，但WZ‐MnTe仍然知之甚少。在本研究中，研究具有WZ-型结构的β-MnTe膜的导电机制。在各种温度下测量WZ-MnTe膜的电阻率、霍尔迁移率和塞贝克系数。在120-300 K的温度范围内电阻率的温度依赖性清楚地表明WZ-MnTe膜显示出可变范围跳跃（弗赫）导电。在此温度范围内，随着温度的降低，在210 K左右，导电机制由Mott-VRH导电转变为Efros-Shklovskii弗赫导电。此外，低的热激活霍尔迁移率，霍尔效应符号异常的发生，以及相对低的热电势激活能，这些都是观察到的结果，表明小极化子跳跃传导在310 K以上占主导地位。
Manganese telluride (MnTe) compound is known to be a polymorphic chalcogenide. Recently, it has been reported that the MnTe shows nonvolatile memory properties with a significant change in resistance via a polymorphic transition between NiAs‐type (NC) structure (low resistance) and wurtzite‐type (WZ) structure (high resistance). This crystalline polymorphic MnTe is expected to realize a phase‐change memory with fast operation speed and ultralow operation energy. While the NC‐MnTe, generally designated as α‐MnTe, is intensively studied, WZ‐MnTe is still poorly understood. Herein this study, electrical conduction mechanism of a β‐MnTe film with a WZ‐type structure is studied. A resistivity, Hall mobility, and Seebeck coefficient of the WZ‐MnTe film are measured at various temperatures. The temperature dependence of resistivity in the temperature range 120–300 K clearly indicates that the WZ‐MnTe film shows a variable‐range hopping (VRH) conduction. In this temperature region, with decreasing temperature, the conduction mechanism changes from Mott–VRH conduction to Efros–Shklovskii VRH conduction at about 210 K. Furthermore, the low thermally activated Hall mobility, occurrence of Hall‐effect sign anomaly, and relatively low activation energy for thermopower, which are the observed results, suggest that the small polaron hopping conduction is dominant above 310 K.