Topics of interest

Superconductivity

A number of characteristic phenomena related to the superconductivity can be investigated using terahertz and infrared spectroscopy. This includes such fundamental features as energy gap and the dynamics of the charge carriers. Another interesting properties are:

• transversal and longitudinal plasma resonances (Sm(La:Sr)CuO₄)
• mixed ac-excitations ((Nd:Ce)CuO₄, (La:Ce)CuO₄)
• quasiparticle relaxation rates
  

Coherence peak in MgB2 Symbols - experiment. Solid line - BCS model with 2Δ/kBTc = 3.53.

Superconducting gap in MgB2 In this case the gap can be seen directly in the spectra. Lines data measured directly using Fourier-Transform spectrometer. Symbols - reflectance as calculated from the results of transmittance experiments using terahertz spectrometer. Note: The conductivity experiments are sensitive to an onset of the absorption, which therefore corresponds to the lowest gap in MgB2. [Ref]

Selected publications

• M. Dressel, N. Drichko, B. Gorshunov, and A. Pimenov
  THz Spectroscopy of Superconductors
  IEEE Selected Topics in Quantum Electronics 14, 399 (2008) 
• A. V. Pronin, A. Pimenov, A. Loidl, A. Tsukada, and M. Naito
  Doping dependence of the gap anisotropy in electron-doped superconductor La_2-xCe_xCuO₄
  Phys. Rev. B 68, 054511 (2003) 
  
• A. Pimenov, A. V. Pronin, A. Loidl, A. Tsukada, and M. Naito
  Far-infrared and submillimeter-wave conductivity in electron-doped cuprate La_2-xCe_xCuO₄
  Europhysics Lett. 64, 246 (2003)
  
• A. Pimenov, A. V. Pronin, A. Loidl, A. Tsukada, and M. Naito
  On the peak in the far-infrared conductivity of strongly anisotropic cuprates
  Phys. Rev B 66, 212508 (2002)
  
• A. Pimenov
  Infrared conductivity and Superconducting Energy Gap in MgB₂
  Adv. in Solid State Phys. 42, 267 (2002)
  
• A. Pimenov, A. Loidl, and S. I. Krasnosvobodtsev
  Superconducting energy gap in MgB₂ film observed by infrared reflectance
  Phys. Rev. B 65, 172502 (2002)
  
• A. Pimenov, A. Loidl, D. Dulic, D. van der Marel, I. M. Sutjahja, and A. A. Menovsky
  Magnetic Field Dependence of the Transverse Plasmon in SmLa_0.8Sr_0.2CuO₄
  Phys. Rev. Lett. 87, 177003, (2001)
  
• A. V. Pronin, A. Pimenov, A. Loidl, and S. I. Krasnosvobodtsev
  Optical conductivity and penetration depth in MgB₂
  Phys. Rev. Lett. 87, 097003 (2001)
  
• D. Dulic, A. Pimenov, D. van der Marel, D. M. Broun, Saeid Kamal, W.N. Hardy, A.A. Tsvetkov, I.M. Sutjaha, R. Liang, A.A. Menovsky, A. Loidl, and S.S. Saxena
  Observation of the Transverse Optical Plasmon in SmLa_0.8Sr_0.2CuO₄
  Phys. Rev. Lett. 86, 4144 (2001)
  
• A. Pimenov, A. V. Pronin, A. Loidl, A. Kampf, S. I. Krasnosvobodtsev, and V. S. Nozdrin
  Submillimeter spectroscopy of tilted Nd_1.85Ce_0.15CuO₄ films: observation of a mixed ac-plane excitation
  Appl. Phys. Lett. 77, 429 (2000)
• A. Pimenov, A. Loidl, B. Shey, B. Stritzker, G. Jakob, H. Adrian, A. V. Pronin, and Yu. G. Goncharov
  Universal relationship between conductivity and penetration depth in YBaCuO
  Europhys. Lett. 48, 73 (1999)
  
• A. Pimenov, A. Loidl, G. Jakob, H. Adrian
  Optical conductivity in YBa₂Cu₃O₇ thin films
  Phys. Rev. B 59,  4390 (1999)
  
• A. V. Pronin, M. Dressel, A. Pimenov, A. Loidl, I. Roshchin, and L. H. Greene
  Direct observation of the superconducting energy gap developing in the conductivity spectra of niobium
  Phys. Rev. B 57, 14416 (1998)