J. Phys. IV France
Volume 131, December 2005
Page(s) 197 - 202
Publié en ligne 18 janvier 2006
International Workshop on Electronic Crystals
S. Brazovskii, P. Monceau and N. Kirova
J. Phys. IV France 131 (2005) 197-202

DOI: 10.1051/jp4:2005131049

Interlayer tunneling spectroscopy of layered CDW materials

Yu.I. Latyshev1, P. Monceau2, S.A. Brazovski3, A.P. Orlov1, A.A. Sinchenko4, Th. Fournier2 and E. Mossang5

1  Institute of Radioengineering and Electronics, Russian Ac. Sci., 125009 Moscow, Russia
2  CRTBT-CNRS, Grenoble, BP. 166, 38042 Grenoble, France
3  LPTMS-CNRS, Bât. 100, Universite Paris-Sud, 91405 Orsay, France
4  Moscow Engineering-Physics Institute, 115409 Moscow, Russia
5  LCMI-CNRS, Grenoble, BP. 166, 38042 Grenoble, France

We have measured intrinsic tunneling spectra of charge density wave (CDW) materials NbSe3 and o-TaS3 in sub-micron scale mesa structures. Beyond the interband tunneling across the CDW gap, $2\Delta$, we observe intragap states at the voltage $V\approx 2\Delta/3$ which we associate with creation of the amplitude soliton. The onset of the tunneling occurs only above a threshold voltage $V_t\approx 0.1\Delta$ followed by a quasi-periodic staircase spectrum. We interpret that behavior as the CDW phase decoupling between neighboring layers via the formation of a grid of dislocation lines. In NbSe3, the application of a high magnetic field (up to 27 T) yields a strong suppression of the tunneling density of states within the CDW gap indicating a possible field induced metal-insulator transition.

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