Static and dynamic structures of CD3ND3GeCl3 studied by TOF high resolution neutron powder diffraction and solid state NMR

Yamada, Koji; Keiko, Mikawa; Okuda, Takuo; Knight, Kevin S.

doi:10.1039/b201611g

Cited by 45 publications

(38 citation statements)

References 18 publications

(11 reference statements)

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“…[51][52][53] More ferroelectric structures have been proposed for various metal, cation or halogen, among which one can find simple examples in Amm2, R3m or Cmc2 1 . 27,47,50,[54][55][56] For 3D materials containing Ge, the tolerance factor is more compatible with the onset of a polar distortion, and a sizable SOC may also be present, especially with the contribution of heavy halogen atoms. 57 More complex cases may correspond to combinations of both antiferrodistortions and ferroelectric behavior.…”

Section: Main Features Of Rashba and Dresselhaus Couplings And Occurementioning

confidence: 95%

“…24 The variety of structures can be described starting from the reference phase 9,44 Pm3m, observed as the high temperature phase of several HOP. [45][46][47][48] From this highly symmetrical structure, different phase transitions can occur being antiferrodistorsive, ferroelectric or antiferrodistorsive and ferroelectric ( Figure 2). If the centrosymmetrical groups Pnma and I4/mcm have been proposed as low and room temperature structures of the notorious CH 3 NH 3 PbI 3 , 49 the same compound has been refined as well in the polar P4mm group.…”

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confidence: 99%

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Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Képénékian

Even

2017

J. Phys. Chem. Lett.

169

181

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In halide hybrid organic-inorganic perovskites (HOP), spin-orbit coupling (SOC) presents a well-documented large influence on band structure. However, SOC may also present more exotic effects, such as Rashba and Dresselhaus couplings. In this perspective, we start by recalling the main features of this effect and what makes HOP materials ideal candidates for the generation and tuning of spin-states. Then, we detail the main spectroscopy techniques able to characterize these effects and their application to HOP. Finally, we discuss potential applications in spintronics and in spin-orbitronics in those non-magnetic systems, that would complete the skill set of HOP and perpetuate its ride on the crest of the wave of popularity started with optoelectronics and photovoltaics. Graphical TOC EntryPage 2 of 29 2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d m a n u s c r i p tThe continuous success of halide hybrid organic-inorganic perovskites (HOP) as solar cell active materials follows several paths. The main activity after 2012 consisted in the search for improvement of the power conversion efficiency (PCE) in typical laboratory configuration (small area, controlled environment). It led to an unprecedented growth of the PCE that has repeatedly reached record values over 22%. 1,2 Meanwhile, another branch of HOP studies have been focused on improving the stability of those cells unfortunately sensitive to light and moisture. 3,4 Opting for various mixtures of halide and cations, 2 various forms, e.g. layered HOP, [5][6][7] or by encapsulating the materials, the stability went from few hours to several thousands hours. Encouraged by these breakthroughs, a third path has pushed the area of hight performance solar cells from less than 1 cm 2 up to 50 cm 2 with a PCE of 12.6%, 8 bringing the perovskite solar cells even closer to commercial use.A common point to all these record HOP materials is the presence of lead. Even though a large effort has been and still is dedicated to the search for efficient lead-free HOP materials, 9,10 their current record PCE remains around 6.4%. 11 It is certainly unfortunate for solar cells because of the known toxicity of lead, 12 even though solutions have early been proposed, 13,14 however, due to the large spin-orbit coupling (SOC) exhibited by Pb, it represents a great opportunity for optoelectronics, spintronics and spin-orbitronics applications where undesired heavy elements can find a place (e.g. arsenic, cadmium).The first identified effect of SOC in HOP materials has been a surprising giant splitting of conduction bands, 15,16 instead of the usual valence band splitting observed in classical semiconductors. 17 It has a strong influence on the band gap energy as well as on the effective masses and the oscillator strength of the optical transitions at the band gap. The chan...

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Section: Main Features Of Rashba and Dresselhaus Couplings And Occurementioning

confidence: 95%

mentioning

confidence: 99%

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Képénékian

Even

2017

J. Phys. Chem. Lett.

169

181

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“…However, given that the organic cations are dynamically disordered in the Pm3m, we perform DFT simulations of this effect for the low-temperature Pnma structure, which corresponds to an antiferrodistorsive distortion of the Pm3m phase. This centrosymmetric structure is often encountered among hybrid organic-inorganic perovskite 56,57,65 and corresponds to the low-temperature phase of CH 3 NH 3 PbI 3 . 65 The Pnma space group corresponds to a D 2h point symmetry.…”

Section: Field-controlled Rashba Spin Splittingmentioning

confidence: 99%

“…To conduct our survey we decided to start from the highly symmetrical Pm3m (n 221) reference phase, 52 observed in the high temperature phase of numerous hybrid perovskites. [54][55][56][57] From this point we follow different phase transitions ( Figure 2). A key point in the observation of a SOC induced spin splitting is the loss of inversion symmetry.…”

Section: Dresselhaus Spin Splittingsmentioning

confidence: 99%

Rashba and Dresselhaus Effects in Hybrid Organic–Inorganic Perovskites: From Basics to Devices

et al. 2015

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We use symmetry analysis, density functional theory calculations and k · p modeling to scrutinize Rashba and Dresselhaus effects in hybrid organic-inorganic halide perovskites. These perovskites are at the center of a recent revolution in the field of photovoltaics but have also demonstrated potential for optoelectronic applications such as transistors and light emitters.Due to a large spin-orbit coupling of the most frequently used metals, they are also predicted to offer a promising avenue for spin-based applications. With an in-depth inspection of the electronic structures and bulk lattice symmetries of a variety of systems, we analyse the origin of the spin splitting in two-and three-dimensional hybrid perovskites. It is shown that low-dimensional nanostructures made of CH 3 NH 3 PbX 3 (X=I, Br) lead to spin splittings that can be controlled by an applied electric field. This new findings further open the door for a perovskite-based spintronics.

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“…Perovskite halides ABX 3 of group IV elements such as Ge, Sn, and Pb have been studied extensively, not only because of their successive phase transitions but also due to the diversity in their electrical properties such as ferroelectricity, ionic and electronic conductivity [1,2]. Successive replacement of hydrogen by CH 3 groups in ammonium ions according to the formula Me x NH 4-x (x = 1-4), leads to a larger ionic radius of the cation, which may result in strong phase transitions.…”

Section: Introductionmentioning

confidence: 99%

Study of molecular dynamics and phase transitions in trimethylammonium trichlorogermanate using ¹H NMR and DSC measurements

Mallikarjunaiah

Ramesh

Damle

2007

Physica Status Solidi (b)

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PACS 64.70. Dv, 76.60.Es, (CH 3 ) 3 NHGeCl 3 is prepared, characterized and studied by 1 H NMR and differential scanning calorimetry to understand the molecular dynamics and phase transitions. The proton spin lattice relaxation time (T 1 ) is measured at 20.53 MHz in the temperature range 391 -5.2 K employing a home-made pulsed NMR spectrometer. The T 1 results show that (CH 3 ) 3 NHGeCl 3 undergoes several phase transitions in the temperature range 391 -50 K. Both T 1 data and DSC thermograms support the occurrence of phase transitions at 272 K and around 323 K. T 1 data are analyzed in three temperature regions using standard models. The T 1 variations in the intermediate temperature region 272 -100 K are attributed to the hindered reorientations of symmetric groups (CH 3 and (CH 3 ) 3 NH). A broad asymmetric T 1 minimum in the temperature region 45 -20 K is attributed to quantum rotational tunneling of the methyl groups.

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Static and dynamic structures of CD3ND3GeCl3 studied by TOF high resolution neutron powder diffraction and solid state NMR

Cited by 45 publications

References 18 publications

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Rashba and Dresselhaus Effects in Hybrid Organic–Inorganic Perovskites: From Basics to Devices

Study of molecular dynamics and phase transitions in trimethylammonium trichlorogermanate using ¹H NMR and DSC measurements

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Static and dynamic structures of CD3ND3GeCl3 studied by TOF high resolution neutron powder diffraction and solid state NMR

Cited by 45 publications

References 18 publications

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Rashba and Dresselhaus Couplings in Halide Perovskites: Accomplishments and Opportunities for Spintronics and Spin–Orbitronics

Rashba and Dresselhaus Effects in Hybrid Organic–Inorganic Perovskites: From Basics to Devices

Study of molecular dynamics and phase transitions in trimethylammonium trichlorogermanate using 1H NMR and DSC measurements

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Study of molecular dynamics and phase transitions in trimethylammonium trichlorogermanate using ¹H NMR and DSC measurements