Formation of metastable conductive nanowire in a thiospinel compound CuIr2S4 induced by ion irradiation

Koshimizu, Masanori; Tsukahara, H.; Asai, Keisuke

doi:10.1016/j.nimb.2009.02.052

Cited by 9 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…19,20 After irradiation of crystalline CuIr 2 S 4 , a sulphospinel which exhibits a temperature-induced metal-insulator transition at 235 K, 21,22 with MeV H + and He ions below T C a slight metastable increase in conductivity was observed and was interpreted as the formation of conductive nanowires produced by the impinging ions. 23 However, a conductivity change only occurred for ion fluences exceeding 10 13 ions/cm 2 , which points to a macroscopic effect rather than individual conducting filaments. Irradiation of the insulating phase of CuIr 2 S 4 at low temperatures of 8.5 K with X-rays also causes a metastable increase of the conductivity accompanied by a transformation to a tetragonal crystal structure.…”

mentioning

confidence: 95%

Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation

et al. 2011

View full text Add to dashboard Cite

We demonstrate the generation of a persistent conductivity increase in vanadium dioxide thin films grown on single crystal silicon by irradiation with 1 GeV 238U swift heavy ions at room temperature. VO2 undergoes a temperature driven metal-insulator-transition (MIT) at 67 °C. After room temperature ion irradiation with high electronic energy loss of 50 keV/nm the conductivity of the films below the transition temperature is strongly increased proportional to the ion fluence of 5·109 U/cm2 and 1·1010 U/cm2. At high temperatures the conductivity decreases slightly. The ion irradiation slightly reduces the MIT temperature. This observed conductivity change is persistent and remains after heating the samples above the transition temperature and subsequent cooling. Low temperature measurements down to 15 K show no further MIT below room temperature. Although the conductivity increase after irradiation at such low fluences is due to single ion track effects, atomic force microscopy (AFM) measurements do not show surface hillocks, which are characteristic for ion tracks in other materials. Conductive AFM gives no evidence for conducting ion tracks but rather suggests the existence of conducting regions around poorly conducting ion tracks, possible due to stress generation. Another explanation of the persistent conductivity change could be the ion-induced modification of a high resistivity interface layer formed during film growth between the vanadium dioxide film and the n-Silicon substrate. The swift heavy ions may generate conducting filaments through this layer, thus increasing the effective contact area. Swift heavy ion irradiation can thus be used to tune the conductivity of VO2 films on silicon substrates

show abstract

mentioning

confidence: 95%

Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation

et al. 2011

View full text Add to dashboard Cite

show abstract

“…It was found that not only x-ray, but also electron, visible light, and even high energy ion beams could induce this IILT phase [15,17,18,29]. We have obtained high-resolution RIXS data in this phase, shown in Fig.…”

mentioning

confidence: 98%

“…When the sample was cooled below T = 50 K while irradiated with x-rays, a sudden drop of resistivity was observed [12,13]. It was found that not only x-ray, but also electron, visible light, and even high energy ion beams could induce this IILT phase [12,14,15,25]. We have obtained high-resolution RIXS data in this phase, shown in Fig.…”

mentioning

confidence: 99%

X-ray-induced electronic structure change in CuIr2S4

et al. 2011

View full text Add to dashboard Cite

The electronic structure of CuIr2S4 has been investigated using various bulk-sensitive x-ray spectroscopic methods near the Ir L3-edge: resonant inelastic x-ray scattering (RIXS), x-ray absorption spectroscopy in the partial fluorescence yield (PFY-XAS) mode, and resonant x-ray emission spectroscopy (RXES). A strong RIXS signal (0.75 eV) resulting from a charge-density-wave gap opening is observed below the metal-insulator transition temperature of 230 K. The resultant modification of electronic structure is consistent with the density functional theory prediction. In the spin-and charge-dimer disordered phase induced by x-ray irradiation below 50 K, we find that a broad peak around 0.4 eV appears in the RIXS spectrum.

show abstract

“…In the bulk, metastable phases form in non-equilibrium processes, e.g., rapid cooling and crystallization from the liquid state [2], or can be stabilized in thin films by epitaxy [3][4][5][6], and via non-equilibrium growth [7][8][9][10][11][12][13]. Metastable phases in nanowires (NWs) have also been achieved by non-equilibrium synthesis [14][15][16][17][18][19][20]. Here we demonstrate a pathway to forming nanoscale metastable solids, which involves the stabilization of the liquid phase [21] and crystallization of an extremely supercooled melt.…”

mentioning

confidence: 99%

Formation and stabilization of single-crystalline metastable AuGe phases in Ge nanowires

Sutter

2011

Nanotechnology

View full text Add to dashboard Cite

We use in situ observations by variable temperature transmission electron microscopy on AuGe alloy drops at the tips of Ge nanowires (NWs) with systematically varying composition to demonstrate the controlled formation of metastable solid phases integrated in NWs. The process, which operates in the regime of vapor-liquid-solid growth, involves a size-dependent depression of the alloy liquidus at the nanoscale that leads to extremely Ge-rich AuGe melts at low temperatures. During slow cooling, these liquid AuGe alloy drops show pronounced departures from equilibrium, i.e., a frustrated phase separation of Ge into the adjacent solid NW, and ultimately crystallize as single-crystalline segments of metastable γ-AuGe. Our findings demonstrate a general avenue for synthesizing NW heterostructures containing stable and metastable solid phases, applicable to a wide range of materials of which NWs form by the vapor-liquid-solid method.

show abstract

Formation of metastable conductive nanowire in a thiospinel compound CuIr2S4 induced by ion irradiation

Cited by 9 publications

References 17 publications

Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation

Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation

X-ray-induced electronic structure change in CuIr2S4

Formation and stabilization of single-crystalline metastable AuGe phases in Ge nanowires

Contact Info

Product

Resources

About