Magnetoresistance of Ge-Si Whiskers in the Vicinity to Metal– Insulator Transition

A.A. Druzhinin; I.P. Ostrovskii; Yu.M. Khoverko; N.S. Liakh-Kaguy

doi:10.15330/pcss.19.2.130-133

Authors

A.A. Druzhinin Lviv National Politechnic University
I.P. Ostrovskii Lviv National Politechnic University
Yu.M. Khoverko Lviv National Politechnic University
N.S. Liakh-Kaguy Lviv National Politechnic University

DOI:

https://doi.org/10.15330/pcss.19.2.130-133

Keywords:

magnetoresistance, whiskers, Ge-Si solid solutions, metal-insulator transition

Abstract

The magnetoresistance of Ge_хSi_1-х (x = 0.002¸ 0.11) whiskers with an acceptor concentration (Na = 3x10¹⁸¸ 2.10¹⁹ cm^-3) near the metal-insulator transition (MIT) was studied at low temperatures (4.2 - 77)K in magnetic fields up to 14 T. It is shown that at 4.2 K the magnetoresistance of the Ge-Si whiskers on thedielectric side of the MIT is quadratic, while the magnetoresistance of the crystals on the metal side of the MIThas an exponential dependence on the magnetic field. In the samples in the immediate vicinity to the MIT on thedielectric side, negative magnetoresistance was detected, whereas in metal samples with a high germaniumcontent (x = 11 at.%) an anomalous positive magnetoresistance occurs. The resulting anomalous dependences arerespectively explained by the conductivity with respect to the delocalized A+ states of the upper Hubbard bandand the increase in the electron-electron interaction in Ge-Si whiskers at increasing germanium content.

References

[1] I. Ennen, D. Kappe, T. Rempel, C. Glenske, and A. Hutten, Sensors (Basel) 16(6), 904 (2016).
[2] N.P. Stepina, E.S. Koptev, A.G. Pogosov, A.V. Dvurechenskii, A.I. Nikiforov, E.Yu. Zhdanov and Y.M. Galperin, J. Phys.: Condens. Matter, 25, 505801 (2013).
[3] A.I. Yakimov, A.V.Dvurechenskii, G.M. Min’kov, J. Exp. Theor. Phys. 100, 722 (2005).
[4] B.I. Shklovskii, A.L. Efros, Electron Properties of Doped Semiconductors (Nauka, Moskow, 1979). (In Russian).
[5] E.E. Rafey, S.A. El.-Atawy. Can. J. Phys. 65, 88 (1987).
[6] T.G. Gastner, W.N. Shafarman, J.S. Brooks, K.P. Martin, Solid State Phys. 5, 366 (1988).
[7] A. Druzhinin, E. Lavitska, I. Maryamova et al., Cryst. Res. Technol. 37, 243 (2002).
[8] A.A. Druzhinin, I.P. Ostrovskii, Physica Status Solidi C 1(2), 333 (2004).
[9] A.A. Druzhinin, I.P. Ostrovskii, N.S. Liakh, Physics and Chemistry of Solid State 4(3), 485 (2003).
[10] A.N. Ionov, I.S. Shlimak, Physics and Technics of Semiconductors 11(4), 741 (1977). (In Russian).
[11] I.E. Trofimov, A.I. Denin, V.P. Murzin, Magnetoresistance in D- band. (Preprint, Moskov, 1989) (in Russian).