Structural characterisation of high-mobility Cd3As2 films crystallised on SrTiO3

Nakazawa, Yusuke; Uchida, Masaki; Nishihaya, Shinichi; Kriener, Markus; Kozuka, Y.; Taguchi, Y.; Kawasaki, Masashi

doi:10.1038/s41598-018-20758-7

Cited by 23 publications

(23 citation statements)

References 31 publications

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“…Zn-doped Cd 3 As 2 thin film was fabricated on a single-crystalline SrTiO 3 (100) substrate by the combination of pulsed laser deposition and solid-phase epitaxy, following the same procedure described in previous papers 15 , 22 , 23 . The film is oriented in the [112] crystallographic direction of Cd 3 As 2 , and the Fermi-arc states on the film surfaces have finite length connecting between the projections of the bulk nodes residing on the [001] axis.…”

Section: Resultsmentioning

confidence: 99%

Intrinsic coupling between spatially-separated surface Fermi-arcs in Weyl orbit quantum Hall states

et al. 2021

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Topological semimetals hosting bulk Weyl points and surface Fermi-arc states are expected to realize unconventional Weyl orbits, which interconnect two surface Fermi-arc states on opposite sample surfaces under magnetic fields. While the presence of Weyl orbits has been proposed to play a vital role in recent observations of the quantum Hall effect even in three-dimensional topological semimetals, actual spatial distribution of the quantized surface transport has been experimentally elusive. Here, we demonstrate intrinsic coupling between two spatially-separated surface states in the Weyl orbits by measuring a dual-gate device of a Dirac semimetal film. Independent scans of top- and back-gate voltages reveal concomitant modulation of doubly-degenerate quantum Hall states, which is not possible in conventional surface orbits as in topological insulators. Our results evidencing the unique spatial distribution of Weyl orbits provide new opportunities for controlling the novel quantized transport by various means such as external fields and interface engineering.

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Section: Resultsmentioning

confidence: 99%

Intrinsic coupling between spatially-separated surface Fermi-arcs in Weyl orbit quantum Hall states

et al. 2021

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“…The epitaxial (Cd 1− x Zn x ) 3 As 2 (112) films were grown on SrTiO 3 (100) single-crystal substrates by the combination of pulsed laser deposition technique and subsequent thermal annealing 14,20,33 . The film thickness is designed to be around 85–100 nm to maintain the three-dimensionality of the bulk state.…”

Section: Discussionmentioning

confidence: 99%

Quantized surface transport in topological Dirac semimetal films

et al. 2019

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Unconventional surface states protected by non-trivial bulk orders are sources of various exotic quantum transport in topological materials. One prominent example is the unique magnetic orbit, so-called Weyl orbit, in topological semimetals where two spatially separated surface Fermi-arcs are interconnected across the bulk. The recent observation of quantum Hall states in Dirac semimetal Cd 3 As 2 bulks have drawn attention to the novel quantization phenomena possibly evolving from the Weyl orbit. Here we report surface quantum oscillation and its evolution into quantum Hall states in Cd 3 As 2 thin film samples, where bulk dimensionality, Fermi energy, and band topology are systematically controlled. We reveal essential involvement of bulk states in the quantized surface transport and the resultant quantum Hall degeneracy depending on the bulk occupation. Our demonstration of surface transport controlled in film samples also paves a way for engineering Fermi-arc-mediated transport in topological semimetals.

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“…The topological protection leads to Fermi arcs on the surface of Cd 3 As 2 crystals [7] and quantum Hall states along the edges [8,9]. Recently, topologically protected states have also been observed in thin films of Cd 3 As 2 [10][11][12]. Thus, Cd 3 As 2 is currently being explored for technological applications based on the topological properties, e.g., for optical switches, electronic devices operating at frequencies in the terahertz regime, and high-sensitivity photodetectors [13][14][15].…”

Section: Introductionmentioning

confidence: 96%

Pressure-induced reconstructive phase transition inCd3As2

Gamża

Abrami

Gammond

et al. 2021

Phys. Rev. Materials

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Cadmium arsenide (Cd 3 As 2) hosts massless Dirac electrons in its ambient-condition tetragonal phase. We report x-ray diffraction and electrical resistivity measurements of Cd 3 As 2 upon cycling pressure beyond the critical pressure of the tetragonal phase and back to ambient conditions. We find that, at room temperature, the transition between the low-and high-pressure phases results in large microstrain and reduced crystallite size, both on rising and falling pressure. This leads to nonreversible electronic properties, including self-doping associated with defects and a reduction of the electron mobility by an order of magnitude due to increased scattering. This paper indicates that the structural transformation is sluggish and shows a sizable hysteresis of over 1 GPa. Therefore, we conclude that the transition is first-order reconstructive, with chemical bonds being broken and rearranged in the high-pressure phase. Using the diffraction measurements, we demonstrate that annealing at ∼200 • C greatly improves the crystallinity of the high-pressure phase. We show that its Bragg peaks can be indexed as a primitive orthorhombic lattice with a HP ≈ 8.68 Å, b HP ≈ 17.15 Å, and c HP ≈ 18.58 Å. The diffraction study indicates that, during the structural transformation, a new phase with another primitive orthorhombic structure may also be stabilized by deviatoric stress, providing an additional venue for tuning the unconventional electronic states in Cd 3 As 2 .

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Structural characterisation of high-mobility Cd3As2 films crystallised on SrTiO3

Cited by 23 publications

References 31 publications

Intrinsic coupling between spatially-separated surface Fermi-arcs in Weyl orbit quantum Hall states

Intrinsic coupling between spatially-separated surface Fermi-arcs in Weyl orbit quantum Hall states

Quantized surface transport in topological Dirac semimetal films

Pressure-induced reconstructive phase transition inCd3As2

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