Pressure induced metallization with absence of structural transition in layered molybdenum diselenide

Abstract

Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures away from the pristine states. Here, we systematically investigated the pressurized behavior of MoSe2 up to ∼60 GPa using multiple experimental techniques and ab-initio calculations. MoSe2 evolves from an anisotropic two-dimensional layered network to a three-dimensional structure without a structural transition, which is a complete contrast to MoS2. The role of the chalcogenide anions in stabilizing different layered patterns is underscored by our layer sliding calculations. MoSe2 possesses highly tunable transport properties under pressure, determined by the gradual narrowing of its band-gap followed by metallization. The continuous tuning of its electronic structure and band-gap in the range of visible light to infrared suggest possible energy-variable optoelectronics applications in pressurized transition-metal dichalcogenides.

Significant improvement in Mn2O3 transition metal oxide electrical conductivity via high pressure

“…Similar logarithmic behavior of pressure dependent resistivity has also been found in VO 2 , MoSe 2 , and GeSb 2 Te 4 232425.…”

High pressure anomalies in exfoliated MoSe2: resonance Raman and x-ray diffraction studies

“…The mode at 147 cm −1 can be seen in case of 532 nm laser excitation, however is not much prominent at 488 nm laser excitation due to several other sharp Raman modes below 200 cm −1 . The modes at 242 and 285 cm −1 are identified as two first order Raman modes A 1g and E g 2 1 , respectively [11,17]. The mode at 147 cm −1 is assigned as…”

“…Pressure can be an excellent tool to study the structural and electronic phase transitions in layered TMD's to understand their behaviour under strained conditions. There are several reports suggesting metallization of TMD's under pressure [7][8][9][10][11][12][13][14][15][16]. Some of the above reports suggest possible structural transition along with metallization with pressure.…”

“…High pressure Raman, electrical resistance, and synchrotron x-ray diffraction (XRD) studies on hexagonal -H MoSe 2 2 (single crystal and powder) do not report any evidence of structural transition accompanying the electronic phase transition [17][18][19]. Later a systematic high pressure investigation on single crystal MoSe 2 up to 60 GPa using multiple experimental techniques and ab-initio calculations reported pressure induced metallization above 40 GPa without any structural transition [11]. However, Aksoy et al [19] have observed a discontinuity in the ratio of Dc c 0 ( )/ Da a 0 ( ) (c and a are the lattice parameters with subscript 0 referring to ambient pressure) at 10 GPa.…”

Hidden orbital polarization in diamond, silicon, germanium, gallium arsenide and layered materials

“…Note that as a byproduct, our calculations give us insight into MoS 2 under a high pressure. A 15% compression of transition metal dichalcogenide compounds has already been achieved in recent high-pressure experiments; 16 the hidden spin polarization of MoS 2 under pressure is likely to be significantly lower than that of MoS 2 not under pressure. To obtain a quantitative prediction, first-principles calculations with structural optimizations are necessary.…”