Giant enhanced g-factors in an InSb two-dimensional gas

Abstract

We report measurements of the electron g-factor in InSb quantum wells using the coincidence technique, polarization transition, and temperature-dependent resistivity. All three methods show that there is a giant enhancement of the spin slitting which is proportional to the spin polarization. Electron Zeeman energies as high as 51 meV are measured leading to the conclusion that the additional contribution to the spin splitting is of order 30 meV, more than ten times larger than expected from conventional theories.

Interplay of spin and orbital magnetogyrotropic photogalvanic effects in InSb/(Al,In)Sb quantum well structures

“…As a possible origin of this effect, we consider exchange interaction between electrons, which is known to lead to a nonlinearity of the Zeeman splitting on the external magnetic field at moderate fields. 11,14 In this case, the effective g * factor besides g 0 , the Landé factor like at B = 0, contains a contribution linear in the spin polarization…”

“…Note that g * * = −30 is obtained in InSb QWs similar to our structures by magnetotransport measurements. 11 Using this value, we calculated how electron temperature influences the average spin. The results are plotted in Fig.…”

“…9. For calculation, we used g 0 = −25 and an effective mass m * = 0.02m 0 determined by magnetotransport experiments 11 and cyclotron resonance data (not shown), respectively. Figure 9(a) shows the average spin calculated for 20-nm QW structures at fixed temperature but for various values of the exchange interaction given by the parameter g * * .…”

“…4 This novel material is the subject of numerous experimental studies of transport, optical, magneto-optical, and spin-related phenomena. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The characteristics driving the interest in this novel narrow gap material are the high carrier mobility, small effective masses, large Landé g * factor, possibility of the mesoscopic spindependent ballistic transport, and a strong spin-orbit coupling. The latter gives rise to a number of optoelectronic effects such as, e.g., terahertz photoconductivity 15 and the circular photogalvanic effect [16][17][18][19][20][21][22] recently observed in InSb QWs.…”

Effects of spin polarization in the HgTe quantum well

“…These findings is useful to compare with similar results obtained recently on the InSb QW, which has a comparable value of g * m * /m 0 but in the Γ 6 conduction band. 7,8 …”