Gate-tunable strong spin-orbit interaction in two-dimensional tellurium probed by weak antilocalization

Abstract

Tellurium (Te) has attracted great research interest due to its unique crystal structure since 1970s. However, the conduction band of Te is rarely studied experimentally because of the intrinsic p-type nature of Te crystal. By atomic layer deposited dielectric doping technique, we are able to access the conduction band transport properties of Te in a controlled fashion. In this paper, we report on a systematic study of weakantilocalization (WAL) effect in n-type two-dimensional (2D) Te films. We find that the WAL agrees well with Iordanskii, Lyanda-Geller, and Pikus (ILP) theory. The gate and temperature dependent WAL reveals that D'yakonov-Perel (DP) mechanism is dominant for spin relaxation and phase relaxation is governed by electron-electron (e-e) interaction. Large phase coherence length near 600nm at T=1K is obtained, together with gate tunable spin-orbit interaction (SOI). Transition from weak-localization (WL) to weak-antilocalization (WAL) depending on gate bias is also observed. These results demonstrate that newly developed solution-based synthesized Te films provide a new controllable strong SOI 2D semiconductor with high potential for spintronic applications.

Highly Efficient Electric-Field Control of Giant Rashba Spin–Orbit Coupling in Lattice-Matched InSb/CdTe Heterostructures

“…As summarized in Table , our InSb/CdTe heterostructures hold both records ( α R = 0.7 eV·Å and d α R /d E = 60 eV·Å 2 ·V –1 ) among all semiconductor-based candidates ( e . g ., narrow-band III–V thin films/quantum wells/nanowires, oxide 2DEG, and large SOC 2D materials), ,,− ,, and our experiment data are comparable with the values estimated in topological hybrid systems. ,, Additionally, given the temperature-insensitive property of the Rashba SOC strength (Figure a), it is reasonable to speculate that the large α R would persist to the high-temperature regime even though the absence of the WAL effect prevents us from quantifying the accurate value above 100 K. Finally, we need to mention that the magneto-transport characterization and the device configuration adopted in this work can only estimate the average Rashba SOC strength of the whole InSb/CdTe quantum well structures, since the electron effective mass is extracted from the overall carrier density through the ordinary Hall effect. In order to further distinguish the α R contributions from the InSb/CdTe and Al 2 O 3 /InSb interfaces, an additional double-gated device and relevant multichannel transport model are needed in the follow-up study.…”

“…e ., Berry phase) at the Fermi level, WAL is served as the hallmark to evaluate the SOC in solid-state systems . As highlighted in the inset of Figure c, the sharp positive MC cusp is well-developed in the low magnetic-field regime and maintains its characteristic line shape up to 80 K. Compared with other reported material candidates, ,− the WAL phenomena observed in the InSb/CdTe sample is most significant in terms of both the large amplitude (Δσ xx = 0.2 e 2 /h) and wide width (magnetic-field range = ± 0.54 T at 1.5 K), as defined in Figure d. In order to quantitatively investigate the large WAL in the mm-size InSb­(15 nm)/CdTe­(1.2 μm) device, we apply the Iordanskii, Lyanda-Geller, and Pikus (ILP) model whose explicit expression is described as where C is the Euler’s constant, Ψ is the digamma function, B so , B φ , B tr are the characteristic effective magnetic fields gauging the first-order interfacial Rashba interaction, phase-coherent transport, and momentum scattering process in the system, respectively, and the coefficient .…”

Air‐Stable 2D Cr5Te8 Nanosheets with Thickness‐Tunable Ferromagnetism

“…Toward this end, several pioneering studies have synthesized ultrathin 2D magnetic materials, for example, layered (VSe 2 and CrSe 2 ) and nonlayered (such as FeTe, Cr 2 S 3 , and CrSe), by using chemical vapor deposition (CVD) approach. [18][19][20][21][22][23][24][25] As tellurium (Te) has very strong spinorbit coupling, [26,27] chromium telluride (Cr x Te y ) should be more inclined to generate strong magnetic anisotropy for stabilizing the long-range magnetic order in 2D systems and would thus yield a high Curie temperature (T C ). More importantly, Cr x Te y contains a series of possible materials with different compositions and structures, such as CrTe 2 , Cr 5 Te 8 , Cr 2 Te 3 , Cr 3 Te 4 , and CrTe, [28] which may bring great opportunities to explore the distinctive magnetic properties of these materials in the 2D limit.…”

Tunable spin-orbit coupling in two-dimensional InSe

“…In contrast to the conventional InAs 15 or HgTe 16 quantum wells, in γ-InSe it is possible to completely suppress the conduction band SOC using applied displacement field, allowing for exceptionally tunable spintronic devices. One of the methods to control the electron spin in semiconductors is to manipulate its spin-orbit coupling (SOC) [17][18][19][20][21][22][23] , and, in this paper, we study the dependence of SOC for two dimensional (2D) electrons near the conduction band edge of InSe films on the number of layers and on the gate-controlled electrostatic doping in the films implemented in the FET geometry [24][25][26][27][28][29][30][31] .…”