TY - JOUR

T1 - Anomalous negative magnetoresistance of two-dimensional electrons

AU - Kanter, Jesse

AU - Vitkalov, Sergey

AU - Bykov, A. A.

PY - 2018/5/24

Y1 - 2018/5/24

N2 - Effects of temperature T (6-18 K) and variable in situ static disorder on dissipative resistance of two-dimensional electrons are investigated in GaAs quantum wells placed in a perpendicular magnetic-field B-¥. Quantum contributions to the magnetoresistance, leading to quantum positive magnetoresistance (QPMR), are separated by application of an in-plane magnetic field. QPMR decreases considerably with both the temperature and the static disorder and is in good quantitative agreement with theory. The remaining resistance R decreases with the magnetic field exhibiting an anomalous polynomial dependence on B-¥:[R(B-¥)-R(0)]=A(T,τq)B-¥η where the power is η≈1.5±0.1 in a broad range of temperatures and disorder. The disorder is characterized by electron quantum lifetime τq. The scaling factor A(T,τq)∼[κ(τq)+β(τq)T2]-1 depends significantly on both τq and T where the first term κ∼τq-1/2 decreases with τq. The second term is proportional to the square of the temperature and diverges with increasing static disorder. Above a critical disorder the anomalous magnetoresistance is absent, and only a positive magnetoresistance, exhibiting no distinct polynomial behavior with the magnetic field, is observed. The presented model accounts memory effects and yields η=3/2.

AB - Effects of temperature T (6-18 K) and variable in situ static disorder on dissipative resistance of two-dimensional electrons are investigated in GaAs quantum wells placed in a perpendicular magnetic-field B-¥. Quantum contributions to the magnetoresistance, leading to quantum positive magnetoresistance (QPMR), are separated by application of an in-plane magnetic field. QPMR decreases considerably with both the temperature and the static disorder and is in good quantitative agreement with theory. The remaining resistance R decreases with the magnetic field exhibiting an anomalous polynomial dependence on B-¥:[R(B-¥)-R(0)]=A(T,τq)B-¥η where the power is η≈1.5±0.1 in a broad range of temperatures and disorder. The disorder is characterized by electron quantum lifetime τq. The scaling factor A(T,τq)∼[κ(τq)+β(τq)T2]-1 depends significantly on both τq and T where the first term κ∼τq-1/2 decreases with τq. The second term is proportional to the square of the temperature and diverges with increasing static disorder. Above a critical disorder the anomalous magnetoresistance is absent, and only a positive magnetoresistance, exhibiting no distinct polynomial behavior with the magnetic field, is observed. The presented model accounts memory effects and yields η=3/2.

KW - MAGNETIC-FIELD

KW - LORENTZ MODEL

KW - GAS

KW - MAGNETOTRANSPORT

KW - LOCALIZATION

KW - HETEROSTRUCTURES

KW - SCATTERING

KW - DYNAMICS

KW - RANGE

KW - ARRAY

UR - http://www.scopus.com/inward/record.url?scp=85047744111&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.97.205440

DO - 10.1103/PhysRevB.97.205440

M3 - Article

AN - SCOPUS:85047744111

VL - 97

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 20

M1 - 205440

ER -