Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session L35: 2D Materials -Superconductivity and Charge Density Waves II
11:15 AM–2:03 PM,
Wednesday, March 7, 2018
LACC Room: 409B
Sponsoring Unit: DMP
Chair: Jun Zhu, Penn State
Abstract: L35.00008 : Suppressed Charge Density Wave and Strain-Enhanced Superconductivity in Na-Intercalated Bilayer NbSe2
1:03 PM–1:15 PM
Atomically thin NbSe2 is a metallic layered transition metal dichalcogenide (TMD) with coexisting superconducting and charge-density-wave (CDW) orders. Using first-principles calculations, we have systematically studied the lattice dynamics, electronic structure and electron-phonon coupling of Na-intercalated bilayer NbSe2. The results show that Na intercalation can effectively suppress the CDW instability of the bilayer NbSe2. In this process, a large electron doping from the intercalated Na contracts the Fermi surface of bilayer NbSe2, causing the reduction of electron-phonon coupling at qCDW. We further find that despite the disappearance of CDW, the superconductivity is still preserved in the NbSe2 intercalate with a predicted transition temperature Tc of 3 K. More interestingly, the biaxial compressive strain is found to largely increase electronic density of states at the Fermi level, soften phonon modes and improve the superconducting Tc of this system by more than 100% at a low strain level of 3%. The present work will stimulate future experimental studies of the synergistic effects of electron doping and strain on CDW and superconductivity in 2D metallic TMD materials.
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