Dimensional crossover in the quasi-one-dimensional superconductor Tl2Mo6Se6

Abstract

We present magnetic penetration depth and electrical transport data in single crystals of quasione-dimensional (q1D) Tl2Mo6Se6, which reveal a 1D→3D superconducting dimensional crossover. The c-axis penetration depth shows the onset of superconducting fluctuations below T ons 1D = 6.7 K, whereas signatures of superconductivity in the ab-plane penetration depth -a uniquely sensitive probe of the transverse phase stiffness -only emerge below T ons 3D = 4.9 K. An anomalously low superfluid density persists down to ∼3 K before rising steeply, in agreement with a theoretical model for crossovers in q1D superconductors. Our data analysis suggest that a sequence of pairing and phase fluctuation regimes controls the unusually broad superconducting transition. In particular, the electrical resistivity below T ons 3D is quantitatively consistent with the establishment of phase coherence through gradual binding of Josephson vortex strings to form 3D loops. This dimensional crossover within the superconducting state occurs despite the relatively large transverse hopping predicted from band structure. Our results have important consequences for the low-temperature normal state in Tl2Mo6Se6 and similar q1D metals, which may retain one-dimensional behavior to lower temperatures than expected from theory.

Superconductivity in Ag implanted Au thin film

“…The Tc was found to be 2.06 K for I = 0.05mA. There is a clear change in the Tc shifting to lower temperatures (like other superconducting systems [39]) when we increase the current from 0.05 mA to 3 mA and with further increase of current to 4 mA, the transition is not observed within our temperature limit of the cryostat. Further we have carried out the voltage (V) versus current (I) measurements of S1-Ag sample at various temperatures around the Tc as presented in Fig.…”

Unravelling the Beneficial Influence of Ag insertion on the Thermoelectric Properties of the Cluster Compound K2Mo15Se19

“…6 Of note, the nearly 1D character of the crystal structure of these compounds gives rise to exotic superconductivity and possibly to novel types of fermionic excitations due to topologically non-trivial electronic band structures. [7][8][9][10] So far, the intermediate Mo9, Mo12, Mo15, Mo18, Mo21, Mo24, Mo30 and Mo36 clusters have been observed in various compounds. [3][4][5][11][12][13] However, the thermoelectric properties of some of these ternary and quaternary molybdenum chalcogenides have only been assessed recently.…”

Pressure engineering of the Dirac fermions in quasi-one-dimensional Tl2Mo6Se6

“…More recently, theoretical works reveal the coexistence of quadratic and cubic Dirac fermions, in addition to the conventional linear Dirac point, in this series of q-1D compounds [6]. More strikingly, topological superconductivity was subsequently proposed in Tl 2 Mo 6 Se 6 by theory, sparking renewed interest in these materials [18][19][20].…”