Electric-Field Control of Spin–Orbit Torques in WS₂/Permalloy Bilayers

Transition metal dichalcogenides (TMDs) have drawn great attention owing to their potential for electronic, optoelectronic, and spintronic applications. In TMDs/ferromagnetic bilayers, an efficient spin current can be generated by the TMDs to manipulate the magnetic moments in the ferromagnetic layer. In this work, we report on the electric-field modulation of spin–orbit torques (SOTs) in WS₂/NiFe bilayers by the spin-torque ferromagnetic resonance technique. It is found that the radio frequency current can induce a spin accumulation at the WS₂/NiFe interface because of the interfacial Rashba–Edelstein effect. As a consequence, the SOT ratio between the field-like and antidamping-like torques can be effectively controlled by applying the back-gate voltage in WS₂/NiFe bilayers. These results provide a strategy for controlling the SOT by using semiconducting TMDs

Sulfur-Doped Black Phosphorus Field-Effect Transistors with Enhanced Stability

Black phosphorus (BP) has drawn great attention owing to its tunable band gap depending on thickness, high mobility, and large <i>I</i>_on/<i>I</i>_off ratio, which makes BP attractive for using in future two-dimensional electronic and optoelectronic devices. However, its instability under ambient conditions poses challenge to the research and limits its practical applications. In this work, we present a feasible approach to suppress the degradation of BP by sulfur (S) doping. The fabricated S-doped BP few-layer field-effect transistors (FETs) show more stable transistor performance under ambient conditions. After exposing to air for 21 days, the charge-carrier mobility of a representative S-doped BP FETs device decreases from 607 to 470 cm² V^–1 s^–1 (remained as high as 77.4%) under ambient conditions and a large <i>I</i>_on/<i>I</i>_off ratio of ∼10³ is still retained. The atomic force microscopy analysis, including surface morphology, thickness, and roughness, also indicates the lower degradation rate of S-doped BP compared to BP. First-principles calculations show that the dopant S atom energetically prefers to chemisorb on the BP surface in a dangling form and the enhanced stability of S-doped BP can be ascribed to the downshift of the conduction band minimum of BP below the redox potential of O₂/O₂^–. Our work suggests that S doping is an effective way to enhance the stability of black phosphorus

Microphotographs (×200) of a representative TNBC case.

<p>A: Hematoxylin-eosin staining. B–D: Immunohistochemical detection for ER, PR and HER-2, respectively. This case is negative for ER, PR and HER-2 (triple negative).</p

Chemoresistance-related miRNAs of the 11 selected miRNAs.

<p>Chemoresistance-related miRNAs of the 11 selected miRNAs.</p

Up-regulation of miR-130a-3p or miR-451a significantly changed MDA-MB-231 cells sensitivity to doxorubicin.

<p>A: Expression levels of miR-130a-3p or miR-451a were evaluated in different cell lines by qRT-PCR (** <i>P</i><0.01; *** <i>P</i><0.001, compared to MCF 10A). B: During doxorubicin treatment, miR-130a-3p or miR-451a were significantly down-regulated in MDA-MB-231 cells, respectively (*** <i>P</i><0.001, compared to vehicle control). C–D: Cells viability and cells apoptotic rate were analyzed by the cell counting kit-8 assay and flow cytometry, respectively (### <i>P</i><0.001, compared to vehicle control; * <i>P</i><0.05, ** <i>P</i><0.01, compared to Doxo group). All the results were obtained from three independent experiments. Doxo, doxorubicin.</p

qRT-PCR validation of miRNAs microarray results in TNBCs.

<p>Relative expression of miRNAs in TNBCs compared with their adjacent normal tissues by qRT-PCR. miR-10b-5p, miR-451a, miR-125b-5p, miR-31-5p, miR-195-5p, miR-130a-3p were down-regulated in cancer samples, whereas miR-155-5p, miR-21-3p, miR-181a-5p, miR-181b-5p and miR-183-5p were up-regulated. Dots, normalized ratio of miRNA expression values (TNBC/adjacent normal tissues).</p

miRNA differential expression in TNBC versus normal breast tissues.

<p>Hierarchical clustering of the 41 miRNAs with a significantly different expression. Rows, individual miRNAs; columns, individual tissue samples. Pseudocolors represent transcript levels above, equal to, and below the mean (red, black, and green, respectively). The scale represents the intensity of miRNA expression (log2 scale ranges between −9 and 5).</p

Additional file 1: Table S1.

Primers for coding sequences of ETV1 and miR-17-5p. (DOC 25 kb

Additional file 2: Table S2.

qRT-PCR primer sequences used in this study. (DOC 26 kb

Additional file 3: Figure S1.

Immunohistochemical staining of ETV1 in two representative TNBC tissues. a, c, Negative control of ETV1. b, d, Positive expression of ETV1. Among the 105 cases of TNBC, 79 cases were ETV1-positive and 26 were ETV1-negative according to the immunoreactivity score described in the text. Scale bar, 10 μm. (TIFF 22543 kb