Modulating Charge Density Wave Order in a 1T-TaS2/Black Phosphorus Heterostructure
journal contributionposted on 01.04.2019, 00:00 by Ziying Wang, Leiqiang Chu, Linjun Li, Ming Yang, Junyong Wang, Goki Eda, Kian Ping Loh
Controllability of collective electron states has been a long-sought scientific and technological goal and promises development of new devices. Herein, we investigate the tuning of charge density wave (CDW) in 1T-TaS2 via a two-dimensional (2D) van der Waals heterostructure of 1T-TaS2/BP. Unusual gate-dependent conductance oscillations were observed in 1T-TaS2 nanoflake supported on BP in transport measurements. Scanning tunneling microscopy study shows that the nearly commensurate (NC) CDW phase survived to 4.5 K in this system, which is substantially lower than the NC to commensurate CDW phase transition temperature of 180 K. A Coulomb blockade model was invoked to explain the conductance oscillations, where the domain walls and domains in NC phase serve as series of quantum dot arrays and tunnelling barriers, respectively. Density functional theory calculations show that a range of interfacial interactions, including strain and charge transfer, influences the CDW stabilities. Our work sheds light on tuning CDW orders via 2D heterostructure stacking and provides new insights on the CDW phase transition and sliding mechanism.
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theory calculations showBPCDW ordersCDW phase transition temperaturecharge transferCoulomb blockade modeldomain wallsCDW phase transitionvan der Waals heterostructure180 KCDW phaseconductance oscillationsquantum dot arraysScanning tunneling microscopy study1 T-TaS 21 T-TaS 2 nanoflakeModulating Charge Density Wave Orderelectron statesCDW stabilities2 D heterostructureNC phase4.5 Ktransport measurementstunnelling barriersUnusual gate-dependent conductance oscillationscharge density wave