Yasuhara Sou, Nakagawa Ayato, Okamoto Kazuki, Shiraishi Takahisa, Funakubo Hiroshi, Yasui Shintaro, Itoh Mitsuru, Tsurumi Takaaki, Hoshina Takuya
School of Materials and Chemical Technology, Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550 Japan
School of Materials and Chemical Technology, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan.
RSC Adv. 2024 May 2;14(20):13900-13904. doi: 10.1039/d4ra02296c. eCollection 2024 Apr 25.
Since the discovery of ferroelectricity in a wurtzite-type structure, this structural type has gathered much attention as a next-generation ferroelectric material due to its high polarization value combined with its high breakdown strength. However, the main targets of wurtzite-type ferroelectrics have been limited thus far to simple nitride/oxide compounds. The investigation of new ferroelectric materials with wurtzite-type structures is important for understanding ferroelectricity in such structures. We therefore focus on β-LiGaO in this study. Although AlN and ZnO possess well-known wurtzite-type structures (6), β-LiGaO has a distorted wurtzite-type structure (2), and there are no reports of ferroelectricity in LiGaO. In this study, we have revealed that LiGaO exhibits relatively high barrier height energy for polarization switching, however, Sc doping effectively reduces that energy. Then, we conducted thin film preparation and evaluation for Sc-doped LiGaO to observe its ferroelectric properties. We successfully observed ferroelectric behavior by using piezoresponse force microscopy measurements for LiGaScO/SrRuO/(111)SrTiO.
自从在纤锌矿型结构中发现铁电性以来，这种结构类型因其高极化值与高击穿强度相结合，作为下一代铁电材料受到了广泛关注。然而，迄今为止，纤锌矿型铁电体的主要研究对象仅限于简单的氮化物/氧化物化合物。研究具有纤锌矿型结构的新型铁电材料对于理解此类结构中的铁电性至关重要。因此，在本研究中我们聚焦于β-LiGaO。虽然AlN和ZnO具有众所周知的纤锌矿型结构（6），但β-LiGaO具有扭曲的纤锌矿型结构（2），并且尚无关于LiGaO中铁电性的报道。在本研究中，我们发现LiGaO在极化切换方面表现出相对较高的势垒高度能量，然而，Sc掺杂有效地降低了该能量。然后，我们对Sc掺杂的LiGaO进行了薄膜制备和评估，以观察其铁电性能。通过对LiGaScO/SrRuO/(111)SrTiO进行压电力显微镜测量，我们成功观察到了铁电行为。
