There is a long-standing confusion concerning the physical origin of the anomalous resistivity peak in transition metal pentatelluride HfTe5. Several mechanisms, such as the formation of charge density wave or polaron...There is a long-standing confusion concerning the physical origin of the anomalous resistivity peak in transition metal pentatelluride HfTe5. Several mechanisms, such as the formation of charge density wave or polaron, have been proposed, but so far no conclusive evidence has been presented. In this work, we investigate the unusual temperature dependence of magneto-transport properties in HfTe5. It is found that a three-dimensional topological Dirac semimetal state emerges only at around Tp （at which the resistivity shows a pronounced peak）, as manifested by a large negative magnetoresistance. This accidental Dirac semimetal state mediates the topological quantum phase transition between the two distinct weak and strong topological insulator phases in HfTe5. Our work not only provides the first evidence of a temperature-induced critical topological phase transition inHfTe5 but also gives a reasonable explanation on the long-lasting question.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921303 and 2013CB921700the National Key Research Program of China under Grant No 2016YFA0300604the'Strategic Priority Research Program(B)'of the Chinese Academy of Sciences under Grant No XDB07020100
文摘There is a long-standing confusion concerning the physical origin of the anomalous resistivity peak in transition metal pentatelluride HfTe5. Several mechanisms, such as the formation of charge density wave or polaron, have been proposed, but so far no conclusive evidence has been presented. In this work, we investigate the unusual temperature dependence of magneto-transport properties in HfTe5. It is found that a three-dimensional topological Dirac semimetal state emerges only at around Tp （at which the resistivity shows a pronounced peak）, as manifested by a large negative magnetoresistance. This accidental Dirac semimetal state mediates the topological quantum phase transition between the two distinct weak and strong topological insulator phases in HfTe5. Our work not only provides the first evidence of a temperature-induced critical topological phase transition inHfTe5 but also gives a reasonable explanation on the long-lasting question.
