Optoelectronic Properties Of Quasi-one Dimensional Charge Density Wave Materials At Cryogenic Temperatures

As a typical collective carrier movement,charge density wave is of great significance for the study of the physical phenomena and mechanisms in strongly correlated electronic systems.With the increasing variety of materials for charge density wave,more and more desirable properties have been shown.In this paper,the photocurrent response of charge density wave states in quasi-one-dimensional materials(TaSe₄)₂I and TaTe₄I at low temperature is explored,and the interaction between photo-electron inside the materials is characterized by a series of experiments.The growth conditions of(TaSe₄)₂I and TaTe₄I single crystals prepared by chemical vapor deposition were investigated.It is found that(TaSe₄)₂I sample exhibits good light response characteristics at low temperature.At 10 K,the resistance of the sample irradiated by laser decreases significantly compared with that without light,and the response time of the sample to light is less than 0.1 ms.The photocurrent response characteristics of the sample show obvious anisotropy,the sample has magneto-optical coupling at low temperature,the single electron and the collective electron excited by laser irradiation drift in the magnetic field,induced positive resistance in the magnetic field.It is observed for the first time that TaTe₄I has a good light response at low temperature.Compared with the conductivity in the dark at 10K,the resistance of the sample irradiated by laser decreases enormously,and the photocurrent response happened in a short time.Due to its quasi-one-dimensional characteristic,the photocurrent response is strongest when the laser direction is parallel to the long axis of the sample,and weakest when it is vertical.The threshold voltage of the sample under light increases with the increase of wavelength.In addition,the photoconductivity of TaTe₄I decreases with the increase of magnetic field intensity.