Strong dopant dependence of electric transport in ion-gated MoS2

Abstract

We report modifications of the temperature-dependent transport properties of MoS2 thin flakes via field-driven ion intercalation in an electric double layer transistor. We find that intercalation with Li+ ions induces the onset of an inhomogeneous superconducting state. Intercalation with K+ leads instead to a disorder-induced incipient metal-to-insulator transition. These findings suggest that similar ionic species can provide access to different electronic phases in the same material.

Anomalous screening of an electrostatic field at the surface of niobium nitride

“…In the past few years, this technique has led to the discovery and control of new phases (including the superconducting one) in various materials. In their native state, most of these featured a low to moderate carrier density ( 10 14 cm −2 ), and ranged from insulating oxides [2][3][4][5], to various layered materials [6][7][8][9][10][11][12][13][14], to cuprate superconductors [15][16][17][18]. A more limited attention has been paid instead to materials with a large intrinsic carrier density, where the effect of the field was generally thought to be undetectable because of the strong electrostatic screening.…”

Ambipolar suppression of superconductivity by ionic gating in optimally doped BaFe2(As,P)2 ultrathin films

“…Intercalation by the BOB − anion can be easily ruled out, since its large size would lead to device failure due to delamination of the layered structure [51]. The Li + cation would not encounter this issue: however, bulk intercalation in EDL transistors is usually activated above certain threshold values of the gate electric field and associated with a sudden increase in disorder [51][52][53], and we would therefore expect it to lead to large deviations from the linear scaling of ∆R/R ′ with ∆n 2D that we instead observe in Fig.4. Additionally, while intercalation can be readily obtained in materials of the 11 family of Fe-based compounds [22,23], it is strongly hindered in the 122 family by the presence of the positively charged, alkaline-earth charge reservoirs: namely, the Sr-122 parent compound is known to be prone to intercalation while the Ba-122 one is not [54], possibly due to the smaller spacing between the layers in the latter.…”

Possible charge-density-wave signatures in the anomalous resistivity of Li-intercalated multilayer MoS2

“…Electrical contacts to the flakes were patterned in Hall bar configuration by e-beam lithography, followed by evaporating Ti(5 nm)/Au(50 nm) and lift-off. A large, interdigitated coplanar side-gate electrode was patterned ∼ 100 µm away from the flake [30]. Then, we deposited a Al 2 O 3 (∼ 60 nm) mask over the electrodes and the rectangular channel of the Hall bar, leaving the irregular part of the flake exposed on all sides.…”

“…As shown in Figs.2b and 2c, for the modulation of the R s as a function of V G , the gating process can be separated into two regimes. For the low V G , the modulation of R s is mainly originated from driving the Li + ions by the applied electric field and accumulating them electrostatically onto the channel surface [29,30]. For large values of V G , the change in R s is instead mainly caused by field-driven ion intercalation to the van der Waals gap between the MoS 2 layers [29,30].…”

“…For the low V G , the modulation of R s is mainly originated from driving the Li + ions by the applied electric field and accumulating them electrostatically onto the channel surface [29,30]. For large values of V G , the change in R s is instead mainly caused by field-driven ion intercalation to the van der Waals gap between the MoS 2 layers [29,30]. When the MoS 2 top surface is directly exposed to the electrolyte, it is difficult to separate the two regimes by considering only the behavior of R s [30], therefore, additional information can be useful for clearer discrimination.…”