Giant, Level-Dependent g Factors in InSb Nanowire Quantum Dots

Abstract

We report on magnetotransport measurements on InSb nanowire quantum dots. The measurements show that the quantum levels of the InSb quantum dots have giant g factors, with absolute values up to approximately 70, the largest value ever reported for semiconductor quantum dots. We also observe that the values of these g factors are quantum level dependent and can differ strongly between different quantum levels. The presence of giant g factors indicates that considerable contributions from the orbital motion of electrons are preserved in the measured InSb nanowire quantum dots, while the level-to-level fluctuations arise from spin-orbit interaction. We have deduced a value of Delta(SO) = 280 mueV for the strength of spin-orbit interaction from an avoided level crossing between the ground state and first excited state of an InSb nanowire quantum dot with a fixed number of electrons.

Measurements of the spin-orbit interaction and Landé g factor in a pure-phase InAs nanowire double quantum dot in the Pauli spin-blockade regime

“…and , * of the T+(1,1) and T+(0,2) states can be different due to the fact that the g factor in a semiconductor nanowire QD is level dependent. 28 In the particular case of the measurements shown in Fig. 4(b), this high current line shifts to lower detuning energy ε with increasing B as shown in Fig.…”

Tunable zero-field Kondo splitting in a quantum dot

“…A conductance enhancement along zero bias is seen inside the N = 9 Coulomb diamond, a feature which is consistent with the spin-1/2 Kondo effect in a quantum dot containing a spinunpaired electron. [4][5][6][7][8][9][10][11] Figure 1(c) shows an enlarged plot of the N = 9 Coulomb diamond, where the quantum dot is in the strong-coupling regime, with the zero-bias Kondo resonance clearly visible inside the Coulomb blockaded region [see also Fig. 1(d)], which shows a line trace along the white dashed line in Fig.…”

“…This conventional effect, usually referred to as the spin-1/2 Kondo effect, is expected to occur for an odd number of electrons on the dot and has been extensively studied in various quantum dot systems. [4][5][6][7][8][9][10][11] In addition to the spin-1/2 Kondo effect, the large tunability of these systems has allowed for studies of different variants of the Kondo effect, such as Kondo correlation effects at singlet-triplet transitions for an even number of electrons on the dot, 6,12-14 the so-called orbital Kondo effect, 15 and the two-channel Kondo effect. 16 Moreover, the exchange coupling between a quantum dot and a nearby impurity, the so-called two-impurity Kondo effect, has attracted interest.…”

Understanding the Mechanisms that Affect the Quality of Electrochemically Grown Semiconducting Nanowires

“…Indium antimonide (InSb) bulk is a promising III-V direct bandgap semiconductor material with zinc blende (FCC) structure [10][11][12][13][14]. InSb has a high room temperature mobility (electron and hole mobility [15] of 77,000 and 850 cm 2 V −1 s −1 , respectively), low electron effective mass [16] of 0.014, and low direct bandgap (E g = 0.17 eV, at 300 K), and large Lande g-factor of 51, [17] making it suitable for use in applications such as high speed, low-power transistors, tunneling field effect transistors (FETs), infrared optoelectronics [18], and magnetoresistive sensors [19].…”