• Electronic properties of GaV4S8: A percolation approach

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      https://www.ias.ac.in/article/fulltext/pram/086/01/0127-0134

    • Keywords

       

      Transition metal compound; percolation theory; magnetoresistance.

    • Abstract

       

      Two polycrystalline V4-cluster compounds of GaV4S8 were prepared at different annealing temperatures (GaV4S8-1 sintered at 800°C and GaV4S8-2 sintered at 500°C). Their temperature-dependent resistivity and structural phase transformation temperature (45 K for GaV4S8-1 and 43K for GaV4S8-2) are found to be very sensitive to the annealing condition. Above 320 K, activation energy 𝜀3 is calculated to be ∼0.23 eV which decreases to ∼0.18 eV around 300 K in GaV4S8-1 and GaV4S8-2 on cooling. According to percolation theory, the gradual decrease in 𝜀3 below 300 K is expected due to the increase in separation between V4-clusters are significantly different in GaV4S8-1 and GaV4S8-2. This statement is strongly supported by the calculated bandwidth 𝛤 per cluster in GaV4S8 (∼0.342 eV in GaV4S8-1 and ∼0.374 eV in GaV4S8-2). A negative magnetoresistance (MR) is also found around 43 K in GaV4S8-2 at 6.0 T magnetic field associated with structural transition.

    • Author Affiliations

       

      I Naik1 S Hansda1 A K Rastogi2

      1. Department of Physics, North Orissa University, Baripada 757 003, India
      2. School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
    • Dates

       
  • Pramana – Journal of Physics | News

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