Enhanced superconductivity in a misfit compound (PbSe)1.12 (TaSe2)2 with double TaSe2 layers

Xiaohui Yang; Jiang Ma; Baijiang Lv; Hanxian Hu; Tulai Sun; Miaocong Li; Lei Qiao; Siqi Wu; Qian Tao; Guang-Han Cao; Zhu-An Xu

doi:10.1209/0295-5075/128/17004

All issues

Volume 128 / No 1 (October 2019)

EPL, 128 1 (2019) 17004

Abstract

Issue		EPL Volume 128, Number 1, October 2019


Article Number		17004
Number of page(s)		7
Section		Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI		https://doi.org/10.1209/0295-5075/128/17004
Published online		27 November 2019

EPL, 128 (2019) 17004

Enhanced superconductivity in a misfit compound (PbSe)_1.12 (TaSe₂)₂ with double TaSe₂ layers

Xiaohui Yang¹^,2, Jiang Ma¹^,2, Baijiang Lv¹^,2, Hanxian Hu¹^,2, Tulai Sun³, Miaocong Li¹^,2, Lei Qiao¹^,2, Siqi Wu¹^,2, Qian Tao¹^,2, Guang-Han Cao¹^,2 and Zhu-An Xu¹^,2^,4^(a)

¹ Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University Hangzhou 310027, PRC
² State Key Laboratory of Silicon Materials, Zhejiang University - Hangzhou 310027, PRC
³ School of Materials Science and Engineering, Zhejiang University - Hangzhou 310027, PRC
⁴ Zhejiang California International NanoSystems Institute, Zhejiang University - Hangzhou 310058, PRC

^(a) zhuan@zju.edu.cn

Received: 13 July 2019
Accepted: 6 October 2019

Abstract

We report the discovery of superconductivity with a maximum T_c ≈ 1.85 K in a new misfit layered compound $(\text{PbSe})_{1.12}(\text{TaSe}_2)_2$ , which consists of alternating layers of a distorted rocksalt layer PbSe and a double-layer dichalcogenide $2H\text{-}\text{TaSe}_2$ . A large anisotropic parameter of resistivity ${\gamma}_\rho = {\rho_c}/{\rho_{ab}} \approx 650$ and that of the upper critical field $\gamma_{H_{c2}}$ = $H_{c2}^{ab} /H_{c2}^{c} \approx 6.6$ are obtained. The estimated c-axis coherence length ${\xi}_c \approx 2.1\ \text{nm}$ is comparable to the c-axis lattice constant. Moreover, the estimated upper critical field $H_{c2}^{ab}(0) = 7.82\ \text{T}$ , significantly exceeding the Pauli paramagnetic limit. All these data indicate a quasi-two-dimensional nature of the superconducting properties in $(\text{PbSe})_{1.12}(\text{TaSe}_2)_2$ . Compared with the physical properties of the misfit compound superconductor $(\text{PbSe})_{1.12}(\text{TaSe}_2)$ with only the half-layer of the $2H\text{-}\text{TaSe}_2$ unit, our study suggests that the enhancement of T_c in $(\text{PbSe})_{1.12}(\text{TaSe}_2)_2$ with double TaSe₂ layers is presumably related to the increase in hole carrier density. The reduced charge transfer from the PbSe layer to the conducting TaSe₂ layer could account for the variation in the charge carrier density.

PACS: 74.78.Fk – Multilayers, superlattices, heterostructures / 74.62.Bf – Effects of material synthesis, crystal structure, and chemical composition / 74.70.Dd – Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.)

© EPLA, 2019

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