Room temperature depinning of the charge-density waves in quasi-two-dimensional 1T-TaS2 devices

Abstract

We report on the depinning of nearly commensurate charge-density waves in 1T-TaS2 thin films at room temperature. A combination of the differential current–voltage measurements with the low-frequency noise spectroscopy provides unambiguous means for detecting the depinning threshold field in quasi-2D materials. The depinning process in 1T-TaS2 is not accompanied by an observable abrupt increase in electric current—in striking contrast to depinning in the conventional charge-density-wave materials with quasi-1D crystal structure. We explained it by the fact that the current density from the charge-density waves in the 1T-TaS2 devices is orders of magnitude smaller than the current density of the free carriers available in the discommensuration network surrounding the commensurate charge-density wave islands. The depinning fields in 1T-TaS2 thin-film devices are several orders of magnitude larger than those in quasi-1D van der Waals materials. Obtained results are important for the proposed applications of the charge-density wave devices in electronics.

Electrical Gating of the Charge-Density-Wave Phases in Two-Dimensional h-BN/1T-TaS2 Devices

“…As mentioned above, it is unlikely that one can change the total current substantially, owing to the high carrier concentration and the large thickness of the samples. The collective CDW current in 2D materials is also small . There is no well-defined de-pinning and sliding of CDW in 2D materials similar to that in metals with quasi-1D crystal structure, which would result in a strong increase in the total current and emergence of the AC component, termed “narrow-band noise” .…”

Charge-Density-Wave Thin-Film Devices Printed with Chemically Exfoliated 1T-TaS2 Ink

“…We measured the low-frequency current fluctuations, i.e., excess electronic noise, to further elucidate the phase transitions in the printed device , Low-frequency noise measurements have been used to understand electronic transport and assess the reliability of the devices. − The details of the experimental setup and measurement procedures have been reported by some of us elsewhere. , At frequencies below 100 kHz, electrically conductive materials often reveal current fluctuations with the spectral density S ( f ) ≈ 1/ f γ , where f is the frequency and parameter γ ≈ 1. Figures (a,b) shows the voltage-referred noise power spectral density, S v , and the normalized current noise power spectral density, S I / I 2 , as a function of frequency at different temperatures.…”

“…We note that a full hysteresis, similar to the one shown in Figure (b), was not observed in the I – V measurements. A full hysteresis induced by passing an electric current is routinely observed in devices fabricated with individual 1T-TaS 2 layers. ,, The fact that we have not observed it in the printed devices is likely related to the inherent disorder of the fillers in the ink, nonuniform heating, and the large size of the devices.…”

“…44−48 The details of the experimental setup and measurement procedures have been reported by some of us elsewhere. 43,48 At frequencies below 100 kHz, electrically conductive materials often reveal current fluctuations with the spectral density S(f) ≈ 1/f γ , where f is the frequency and parameter γ ≈ 1. Figures 5(a,b) shows the voltage-referred noise power spectral density, S v , and the normalized current noise power spectral density, S I /I 2 , as a function of frequency at different temperatures.…”

Printed Electronic Devices with Inks of TiS3 Quasi-One-Dimensional van der Waals Material

“…We used low-frequency electronic noise spectroscopy to further elucidate the electron transport properties in our printed devices. The details of our experimental setup and measurement procedures have been reported elsewhere in the context of other material systems. , The analysis of the noise spectral density, its functional dependence on frequency, electric bias, and temperature can provide a wealth of information on the electron transport, particularly in material systems with high concentrations of defects and impurities, which act at the charge trapping sites. We have successfully used electronic noise spectroscopy for monitoring phase transitions in materials, which reveal strongly correlated phenomena. ,− Typically, at the frequencies f < 100 kHz, materials show the spectral noise density of S ( f ) ∼ 1/ f γ type, with γ ∼ 1.…”