Direct Correlation of Structural Domain Formation with the Metal Insulator Transition in a VO₂ Nanobeam

The electrical resistance of single VO2 nanobeams was measured while simultaneously mapping the domain structure with Raman spectroscopy to investigate the relationship between structural domain formation and the metal−insulator transition. With increasing temperature, the nanobeams transformed from the insulating monoclinic M1 phase to a mixture of the Mott-insulating M2 and metallic rutile phases. Domain fractions were used to extract the temperature dependent resistivity of the M2 phase, which showed an activated behavior consistent with the expected Mott−Hubbard gap. Metallic monoclinic phases were also produced by direct injection of charge into devices, decoupling the Mott metal−insulator transition from the monoclinic to rutile structural phase transition

Spatial distribution of <i>α</i>-diversity in subalpine meadows.

α-Diversity indices included Simpson, Shannon, Pielou, and Patrick indices. The data were collected from six quadrats on each of nine mountain sites (54 quadrats in total); means for each mountain site were used in the analysis. Therefore, each α-diversity index had nine values, one for each site.</p

Spatial distribution of biomass in subalpine meadows.

Mountain names indicated by abbreviated letters are shown in Table 1. AB, BB, TB, and R/S represent aboveground, belowground, and total biomass, as well as the root:shoot ratio, respectively. Different or the same small letters indicate significant and insignificant differences (PP>0.05), respectively. The data are shown with mean ± S.E. with six values given for each mountain.</p

Demarcations on geographical gradient belts of various mountains.

Latitudinal, longitudinal, and elevational gradients were divided into five, five, and six belts with intervals of 0.5°, 0.45°, and 100 m, respectively. The initial belts were all numbered 1 with different gradient ranges. Mountain names indicated by abbreviated letters are shown in Table 1.</p

Correlation and significance analyses of <i>α</i>-diversity with elevation and among various mountains, respectively.

α-Diversity indices included the Patrick, Simpson, Shannon, and Pielou indices. Mountains were DD, BT, DT, ML, HY, YZ, YD, SU, and SE; mountain names indicated by abbreviated letters are shown in Table 1. Different or the same small letters present significant or insignificant differences (PP>0.05), respectively. The data for correlation coefficients in the analyses of α-diversity with elevation are listed with the corresponding P values in brackets. In significance analyses of α-diversity among various mountains, significance levels were expressed with different small letters. The data were collected from six quadrats on each of nine mountain sites (54 quadrats in total); means for each mountain site were used in the analysis. Therefore, each mountain site had one elevation, so nine α-diversity values were used in each correlation analysis. However, the six plots in each mountain were not averaged, so six value were used in each significance analysis for each site.</p

Variations of <i>α</i>-diversity with latitude and longitude in subalpine meadows.

α-Diversity indices included the Patrick, Simpson, Shannon, and Pielou indices. The data were collected from six quadrats on each of nine mountain sites (54 quadrats in total) with different latitude and longitude; means for each mountain site were used in the analysis. Therefore, each index had nine values, one for each site.</p

Spatial distribution of <i>γ</i>-diversity in subalpine meadows.

The study employed corresponding belts along five latitudinal, five longitudinal, and six elevational gradients, with five, five, and six values respectively. Each belt had one value.</p

Regression analysis between <i>α</i>-diversity and biomass in subalpine meadows.

The data were collected from six quadrats on each of nine mountain sites (54 quadrats in total); means for each mountain site were used in the analysis. Therefore, each α-diversity and biomass index had 54 values. Significant relationships were selected between α-diversity and biomass indices.</p

Study area and experimental plots.

Light and dark colors show low and high elevation, respectively.</p

Changes on spatial distribution of <i>β</i>-diversity in subalpine meadows.

β-Diversity indices included the Cody, Sørenson, and Bray-Curtis indices. Numbers from 1 to 6 in x-coordinates represented corresponding numbers of latitudinal, longitudinal, and elevational belts in Table 2. Intervals of 1–2, 2–3, 3–4, 4–5, and 5–6 indicated comparisons between adjacent belts, whereas 1–2, 1–3, 1–4, 1–5, and 1–6 indicated comparisons of the initial belt (belt 1) with other belts. The study employed five latitudinal, five longitudinal, and six elevational belts. Each index had values for four latitudinal, four longitudinal, and five elevational belts.</p