Quantum Magnetoresistance of GaPAs Whiskers

Abstract

The magnetoresistance of GaPxAs1-x (x = 0…0.45) whiskers with doping concentration of silicon in the range from the deep dielectric side of metal-insulated transition (~1017 сm-3) to its critical concentration (Nc ~ 5´1018 сm-3) at cryogenic temperatures of 4.2¸77 K and magnetic field induction of 0¸14 T was studied. A negative magnetic resistance (NMR) with maximum value of 7 % was found at temperature 4.2 K and magnetic field 4.5 T, which is dependent on magnetic field induction and current direction. The NMR absolute value reduces with increasing temperature was observed in the transverse and longitudinal magnetoresistance. The nature of the revealed NMR effect was discussed in the studied samples. There are four possible reasons of the NMR effect in the GaPxAs1-x whiskers such as the dimensional quantization, the magnetic ordering of electron spins or magnetic ordering due to uncontrolled magnetic dopant introduction and quantum interference of the electron wave function. The GaPxAs1-x whisker application as the temperature sensor was proposed due to the studied results of the temperature dependence of their conductivity.

Keywords

• gapas whiskers
• magnetoresistance
• metal-insulated transition
• sensor
• cryogenic temperatures