Coexistence of Superconductivity with Enhanced Charge Density Wave Order in the Two-Dimensional Limit of TaSe2

Chao-Sheng Lian; Christoph Heil; Xiaoyu Liu; Chen Si; Feliciano Giustino; Wenhui Duan

Coexistence of Superconductivity with Enhanced Charge Density Wave Order in the Two-Dimensional Limit of TaSe2

Chao-Sheng Lian, Christoph Heil, Xiaoyu Liu, Chen Si, Feliciano Giustino, Wenhui Duan

Institute of Theoretical and Computational Physics (5150)

Research output: Contribution to journal › Letter

Abstract

Bulk 2H-TaSe2 is a model charge density wave
(CDW) metal with superconductivity emerging at extremely low
temperature (Tc = 0.1 K). Here, by first-principles calculations
including the explicit calculation of the screened Coulomb
interaction, we demonstrate enhanced superconductivity in the
CDW state of monolayer 1H-TaSe2 observed in recent experi-
ments. Its ground-state 3 × 3 CDW phase features triangular
clustering of Ta atoms and possesses a large electron−phonon
coupling of λ = 0.74, yielding an order of magnitude higher
superconducting Tc compared to the bulk. Upon lowering the
thickness from bulk to monolayer TaSe2, the CDW intensifies with
slightly decreased Fermi-level density of states, while super-
conductivity gets boosted via a largely increased intrinsic
electron−phonon coupling strength, which overcomes both the CDW effect and naturally reinforced Coulomb repulsion.
These results uncover the simultaneously enhanced CDW and superconducting orders in the two-dimensional limit for the first
time and have key implications for other CDW metals like 2H-TaS2.

Original language	English
Article number	9b01480
Pages (from-to)	4076
Number of pages	4081
Journal	Journal of Physical Chemistry Letters
Volume	10
Issue number	14
Publication status	Published - 5 Jul 2019

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@article{365a4d3153ab479e974eb5df9c352b1b,

title = "Coexistence of Superconductivity with Enhanced Charge Density Wave Order in the Two-Dimensional Limit of TaSe2",

abstract = "Bulk 2H-TaSe2 is a model charge density wave(CDW) metal with superconductivity emerging at extremely lowtemperature (Tc = 0.1 K). Here, by first-principles calculationsincluding the explicit calculation of the screened Coulombinteraction, we demonstrate enhanced superconductivity in theCDW state of monolayer 1H-TaSe2 observed in recent experi-ments. Its ground-state 3 × 3 CDW phase features triangularclustering of Ta atoms and possesses a large electron−phononcoupling of λ = 0.74, yielding an order of magnitude highersuperconducting Tc compared to the bulk. Upon lowering thethickness from bulk to monolayer TaSe2, the CDW intensifies withslightly decreased Fermi-level density of states, while super-conductivity gets boosted via a largely increased intrinsicelectron−phonon coupling strength, which overcomes both the CDW effect and naturally reinforced Coulomb repulsion.These results uncover the simultaneously enhanced CDW and superconducting orders in the two-dimensional limit for the firsttime and have key implications for other CDW metals like 2H-TaS2.",

author = "Chao-Sheng Lian and Christoph Heil and Xiaoyu Liu and Chen Si and Feliciano Giustino and Wenhui Duan",

year = "2019",

month = "7",

day = "5",

language = "English",

volume = "10",

pages = "4076",

journal = "The journal of physical chemistry letters",

issn = "1948-7185",

publisher = "American Chemical Society",

number = "14",

}

TY - JOUR

T1 - Coexistence of Superconductivity with Enhanced Charge Density Wave Order in the Two-Dimensional Limit of TaSe2

AU - Lian, Chao-Sheng

AU - Heil, Christoph

AU - Liu, Xiaoyu

AU - Si, Chen

AU - Giustino, Feliciano

AU - Duan, Wenhui

PY - 2019/7/5

Y1 - 2019/7/5

N2 - Bulk 2H-TaSe2 is a model charge density wave(CDW) metal with superconductivity emerging at extremely lowtemperature (Tc = 0.1 K). Here, by first-principles calculationsincluding the explicit calculation of the screened Coulombinteraction, we demonstrate enhanced superconductivity in theCDW state of monolayer 1H-TaSe2 observed in recent experi-ments. Its ground-state 3 × 3 CDW phase features triangularclustering of Ta atoms and possesses a large electron−phononcoupling of λ = 0.74, yielding an order of magnitude highersuperconducting Tc compared to the bulk. Upon lowering thethickness from bulk to monolayer TaSe2, the CDW intensifies withslightly decreased Fermi-level density of states, while super-conductivity gets boosted via a largely increased intrinsicelectron−phonon coupling strength, which overcomes both the CDW effect and naturally reinforced Coulomb repulsion.These results uncover the simultaneously enhanced CDW and superconducting orders in the two-dimensional limit for the firsttime and have key implications for other CDW metals like 2H-TaS2.

AB - Bulk 2H-TaSe2 is a model charge density wave(CDW) metal with superconductivity emerging at extremely lowtemperature (Tc = 0.1 K). Here, by first-principles calculationsincluding the explicit calculation of the screened Coulombinteraction, we demonstrate enhanced superconductivity in theCDW state of monolayer 1H-TaSe2 observed in recent experi-ments. Its ground-state 3 × 3 CDW phase features triangularclustering of Ta atoms and possesses a large electron−phononcoupling of λ = 0.74, yielding an order of magnitude highersuperconducting Tc compared to the bulk. Upon lowering thethickness from bulk to monolayer TaSe2, the CDW intensifies withslightly decreased Fermi-level density of states, while super-conductivity gets boosted via a largely increased intrinsicelectron−phonon coupling strength, which overcomes both the CDW effect and naturally reinforced Coulomb repulsion.These results uncover the simultaneously enhanced CDW and superconducting orders in the two-dimensional limit for the firsttime and have key implications for other CDW metals like 2H-TaS2.

M3 - Letter

VL - 10

SP - 4076

JO - The journal of physical chemistry letters

JF - The journal of physical chemistry letters

SN - 1948-7185

IS - 14

M1 - 9b01480

ER -