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Gated tuned superconductivity and phonon softening in monolayer and bilayer MoS2
- Source :
- npj Quantum Materials, Vol 2, Iss 1, Pp 1-7 (2017)
- Publication Year :
- 2017
- Publisher :
- Nature Publishing Group, 2017.
-
Abstract
- Superconductors at the atomic two-dimensional limit are the focus of an enduring fascination in the condensed matter community. This is because, with reduced dimensions, the effects of disorders, fluctuations, and correlations in superconductors become particularly prominent at the atomic two-dimensional limit; thus such superconductors provide opportunities to tackle tough theoretical and experimental challenges. Here, based on the observation of ultrathin two-dimensional superconductivity in monolayer and bilayer molybdenum disulfide (MoS2) with electric-double-layer gating, we found that the critical sheet carrier density required to achieve superconductivity in a monolayer MoS2 flake can be as low as 0.55 × 1014 cm−2, which is much lower than those values in the bilayer and thicker cases in previous report and also our own observations. Further comparison of the phonon dispersion obtained by ab initio calculations indicated that the phonon softening of the acoustic modes around the M point plays a key role in the gate-induced superconductivity within the Bardeen–Cooper–Schrieffer theory framework. This result might help enrich the understanding of two-dimensional superconductivity with electric-double-layer gating. Experiments show that a softening of phonon modes aids gate-induced superconductivity in two-dimensional materials. As a material’s dimensions are reduced, the role of disorder and electronic correlations in defining the electronic properties become more prominent, and as the density of charge carriers is much lower, superconductivity is less likely to emerge. An international team of researchers led by Feng Mio and Baigeng Wang from Nanjing University and Harold Hwang from SLAC National Accelerator laboratory and Stanford University use an ionic liquid-based setup, which allows for high gate voltages to be applied, to demonstrate gate-induced superconductivity in monolayers and bilayers of a transition metal dichalcogenide. They show that a softening of the acoustic phonon modes allows for superconductivity to be realized in single layers with a lower carrier density than that needed in multilayers.
- Subjects :
- Materials science
Phonon
FOS: Physical sciences
02 engineering and technology
lcsh:Atomic physics. Constitution and properties of matter
01 natural sciences
chemistry.chemical_compound
Condensed Matter::Materials Science
Ab initio quantum chemistry methods
Condensed Matter::Superconductivity
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
0103 physical sciences
Monolayer
lcsh:TA401-492
010306 general physics
Molybdenum disulfide
Softening
Superconductivity
Condensed Matter - Mesoscale and Nanoscale Physics
Condensed matter physics
Bilayer
021001 nanoscience & nanotechnology
Condensed Matter Physics
Electronic, Optical and Magnetic Materials
lcsh:QC170-197
chemistry
Charge carrier
lcsh:Materials of engineering and construction. Mechanics of materials
0210 nano-technology
Subjects
Details
- Language :
- English
- ISSN :
- 23974648
- Volume :
- 2
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- npj Quantum Materials
- Accession number :
- edsair.doi.dedup.....185c12d661cf85eef849bcd4d5e33fc2