Transport and magnetotransport effects in indium antimonide doped with manganese within quasimetal‐insulator transition

Abstract

InSb crystals doped with manganese within the critical concentration of metal‐insulator transition (Ncr = 2×1017 cm‐3) demonstrate colossal negative magnetoresitance and Hall constant sign inversion at low temperatures in magnetic field – unusual for nonmagnetic materials. Studies of the magnetotransport and conductivity dependency on temperature and manganese concentration revealed that both holes and electrons influence the effects. An excitonic insulator phase conception is proposed as a new approach for the explanation of conductivity and magnetotransport anomalies in p‐InSb(Mn). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Negative magnetoresistance in indium antimonide whiskers doped with tin

“…The magnetotransport characteristics of p-InSb(Ge) crystals at low temperatures differ from p-InSb(Mn) characteristics [6]. InSb crystals doped by Ge do not demonstrate resistivity dependense on impurity concentration, temperature and magnetic field, but it demonstrates the variable range hopping conductivity, and positive magneotresistance typical for disordered localized nonmagnetic impurities.…”

“…Negative magnetoresistance (NMR) was observed in InSb crystals at low temperatures and weak magnetic fields [1][2][3][4][5][6][7][8][9]. There are various interpretations of this effect due to different mechanisms of scattering of charge carriers.…”

“…There are various interpretations of this effect due to different mechanisms of scattering of charge carriers. In particular: 1) surface boundary scattering [1,2]; 2) scattering on magnetic impurities [3][4][5]; 3) scattering on nonmagnetic impurities with concentration in the vicinity to metal-insulator transition (MIT) [5][6][7][8][9].…”

“…Magnetoresistance of nonmagnetic InSb single crystal doped with manganese with impurity concentration 1.5⋅10 17 cm −3 was investigated in the temperature range 40 mK-300 K and magnetic fields 0-25 T [5][6][7][8]. Colossal decrease of resistivity in p-type InSb(Mn) crystals was revealed in magnetic fields 0-4 T at superlow temperatures [5].…”

A new type of low temperature conductivity in InSb doped with Mn

“…However, our studies of manganese-doped InSb crystals in a narrow range of manganese concentrations on the insulator side of MIT revealed 5 that p-InSb(Mn) can display an unusual temperature resistivity dependence, which cannot be explained in the framework of the VRH model. Later 6,7 it has been shown that the temperature -resistivity dependence observed in the temperature range 10÷1,5K can be described by an exponential quadratic function…”