A disorder-enhanced quasi-one-dimensional superconductor

Abstract

A powerful approach to analysing quantum systems with dimensionality d>1 involves adding a weak coupling to an array of one-dimensional (1D) chains. The resultant quasi-1D (q1D) systems can exhibit long-range order at low temperature, but are heavily influenced by interactions and disorder due to their large anisotropies. Real q1D materials are therefore ideal candidates not only to provoke, test and refine theories of strongly correlated matter, but also to search for unusual emergent electronic phases. Here we report the unprecedented enhancement of a superconducting instability by disorder in single crystals of Na2−δMo6Se6, a q1D superconductor comprising MoSe chains weakly coupled by Na atoms. We argue that disorder-enhanced Coulomb pair-breaking (which usually destroys superconductivity) may be averted due to a screened long-range Coulomb repulsion intrinsic to disordered q1D materials. Our results illustrate the capability of disorder to tune and induce new correlated electron physics in low-dimensional materials.

Effects of pressure and magnetic field on superconductivity in ZrTe3: local pair-induced superconductivity

“…On the other hand, a similar two-stage resistive transition of SC has been reported in the Q1D materials family such as Tl 2 Mo 6 Se 6 and Na 2 Mo 6 Se 6 [35,36]. As temperature decreases, the resistivity reduces but does not become zero in Tl 2 Mo 6 Se 6 .…”

Multiband One-Dimensional Electronic Structure and Spectroscopic Signature of Tomonaga-Luttinger Liquid Behavior in K2Cr3AsWatson1, Feng2, Nicholson3 et al. 2017Phys. Rev. Lett.Self Cite583410View full textAdd to dashboardCite

“…Therefore, the best starting point for understanding superconductivity may be with TLLs hosted by 1-D Cr 3 As 3 stacks [7,11] and only weakly coupled by the K guest ions, rather than with quasiparticles occupying 3-D Fermi surfaces [8,34]. In Q1D superconductors, the guest ion type and disorder are crucial for controlling superconductivity, as exemplified in the M 2 Mo 6 Se 6 family with guest ion M ¼ Tl, In, Na, K, Rb [35][36][37]. Further ARPES and STM studies of the A x Cr 3 As 3 family, changing the guest ions to Rb 2 , Cs 2 , K [38][39][40], could illuminate its superconducting state.…”

Electron and thermal transport via variable range hopping in MoSe2 single crystals

“…Petrovic et.al. 39 show that for Na 2−δ Mo 6 Se 6 , resistivity ρ(T ) as T → 0 K, increases monotonically with degree of disorder. In our case disorder parameter T 0 is of the order of 10 4 , which corresponds to a finite ρ at low temperature.…”

“…This semiconductor to metal phase transition at T ∼ 31 K observed in our experiment is highly intriguing which maybe attributed to disorder controlled divergence in resistivity as discussed by earlier works on phase transitions in disordered systems [34][35][36][37][38] . In two dimensional quasi-1D systems of the MoSe 2 family, superconducting phase transition has been observed at lower temperatures [39][40][41][42][43] . Petrovic et.al.…”