We report a comprehensive study on a layered-structure compound of NaZn_(4)As_(3),which has been predicted to be an ideal topological semimetal(TSM) candidate.It is found that NaZn_(4)As_(3) undergoes a structural tra...We report a comprehensive study on a layered-structure compound of NaZn_(4)As_(3),which has been predicted to be an ideal topological semimetal(TSM) candidate.It is found that NaZn_(4)As_(3) undergoes a structural transformation from high temperature rhombohedral to a low temperature monoclinic phase.The electric resistivity exhibits a metal-to-insulatorlike transition at around 100 K,and then develops a plateau at low temperature,which might be related to the protected topologically conducting surface states.Our first-principles calculation confirms further that NaZn_(4)As_(3) is a topological insulator(TI) for both different phases rather than a previously proposed TSM.The Hall resistivity reveals that the hole carriers dominate the transport properties for the whole temperature range investigated.Furthermore,an obvious kink possibly associated to the structure transition has been detected in thermopower around ~ 170 K.The large thermopower and moderate κ indicate that NaZn_(4)As_(3) and/or its derivatives can provide a good platform for optimizing and studying the thermoelectric performance.展开更多
We report the transport properties of a topological insulator candidate,LiMgBi.The electric resistivity of the title compound exhibits a metal-to-semiconductor-like transition at around 160 K and tends to saturation b...We report the transport properties of a topological insulator candidate,LiMgBi.The electric resistivity of the title compound exhibits a metal-to-semiconductor-like transition at around 160 K and tends to saturation below 50 K.At low temperatures,the magnetoresistance is up to~260%at 9 T and a clear weak antilocalization effect is observed in the low magnetic-field region.The Hall measurement reveals that LiMgBi is a multiband system,where hole-type carriers(nh~1018 cm^(-3))play a major role in the transport process.Remarkably,LiMgBi possess a large Seebeck coefficient(~440μV/K)and a moderate thermal conductivity at room temperature,which indicate that LiMgBi is a promising candidate in thermoelectric applications.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11874417 and 12274440)the Strategic Priority Research Program (B) of Chinese Academy of Sciences (Grant No. XDB33010100)the Fund from the Ministry of Science and Technology of China (Grant No. 2022YFA1403903)。
文摘We report a comprehensive study on a layered-structure compound of NaZn_(4)As_(3),which has been predicted to be an ideal topological semimetal(TSM) candidate.It is found that NaZn_(4)As_(3) undergoes a structural transformation from high temperature rhombohedral to a low temperature monoclinic phase.The electric resistivity exhibits a metal-to-insulatorlike transition at around 100 K,and then develops a plateau at low temperature,which might be related to the protected topologically conducting surface states.Our first-principles calculation confirms further that NaZn_(4)As_(3) is a topological insulator(TI) for both different phases rather than a previously proposed TSM.The Hall resistivity reveals that the hole carriers dominate the transport properties for the whole temperature range investigated.Furthermore,an obvious kink possibly associated to the structure transition has been detected in thermopower around ~ 170 K.The large thermopower and moderate κ indicate that NaZn_(4)As_(3) and/or its derivatives can provide a good platform for optimizing and studying the thermoelectric performance.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0300604)the National Natural Science Foundation of China(Grant No.11874417)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB33010100)。
文摘We report the transport properties of a topological insulator candidate,LiMgBi.The electric resistivity of the title compound exhibits a metal-to-semiconductor-like transition at around 160 K and tends to saturation below 50 K.At low temperatures,the magnetoresistance is up to~260%at 9 T and a clear weak antilocalization effect is observed in the low magnetic-field region.The Hall measurement reveals that LiMgBi is a multiband system,where hole-type carriers(nh~1018 cm^(-3))play a major role in the transport process.Remarkably,LiMgBi possess a large Seebeck coefficient(~440μV/K)and a moderate thermal conductivity at room temperature,which indicate that LiMgBi is a promising candidate in thermoelectric applications.
基金supported by the National Natural Science Foundation of China (12141002,52088101,11874417,11974389,and 52172216)the Ministry of Science and Technology of China (2021YFA0718702)+5 种基金the Chinese Academy of Sciences through the Strategic Priority Research Programthe Scientific Instrument Developing Programthe Project for Young Scientists in Basic Research (XDB33000000,YJKYYQ20200017,and YSBR-057)the Chinese Postdoctoral Science Foundation (E0BK181)the funding support of the National Key Research and Development Program of China (2018YFA0702100)the support from the Key Research Project of Zhejiang Laboratory (2021PE0AC02)。
