Ph.D. in Theoretical and Computational Chemistry / Materials Science
B.S. in Theoretical and Computational Chemistry / Chemical Biology
18+ high-profile publications (Nat. Chem., Nat. Commun., Phys. Rev., JACS, etc.)
1000+ citations.

Proficient in 1) quantum chemistry simulation; 2) quantum chemistry code development; 3) molecular mechanics simulation

6 years of research experience on DFT and solid-state materials/semiconductors;
5 years of research experience on MD and biological systems.
Recently march towards Machine-Learning-aided molecular simulation, property prediction, and material discovery.

Contact: AT

Professional Education

  • Doctor of Philosophy, Duke University (2023)
  • Bachelor of Science, Peking University (2017)
  • Ph.D., Duke University, Theoretical and Computational Chemistry / Materials Science (2023)
  • B.S., Peking University, Theoretical and Computational Chemistry / Chemical Biology (2017)

Stanford Advisors

All Publications

  • Thickness control of organic semiconductor-incorporated perovskites. Nature chemistry Park, J. Y., Song, R., Liang, J., Jin, L., Wang, K., Li, S., Shi, E., Gao, Y., Zeller, M., Teat, S. J., Guo, P., Huang, L., Zhao, Y. S., Blum, V., Dou, L. 2023


    Two-dimensional organic semiconductor-incorporated perovskites are a promising family of hybrid materials for optoelectronic applications, owing in part to their inherent quantum well architecture. Tuning their structures and properties for specific properties, however, has remained challenging. Here we report a general method to tune the dimensionality of phase-pure organic semiconductor-incorporated perovskite single crystals during their synthesis, by judicious choice of solvent. The length of the conjugated semiconducting organic cations and the dimensionality (n value) of the inorganic layers can be manipulated at the same time. The energy band offsets and exciton dynamics at the organic-inorganic interfaces can therefore be precisely controlled. Furthermore, we show that longer and more planar π-conjugated organic cations induce a more rigid inorganic crystal lattice, which leads to suppressed exciton-phonon interactions and better optoelectronic properties as compared to conventional two-dimensional perovskites. As a demonstration, optically driven lasing behaviour with substantially lower lasing thresholds was realized.

    View details for DOI 10.1038/s41557-023-01311-0

    View details for PubMedID 37653228

    View details for PubMedCentralID 9113178

  • Structure and electronic tunability of acene alkylamine based layered hybrid organic-inorganic perovskites from first principles PHYSICAL REVIEW MATERIALS Song, R., Liu, C., Kanai, Y., Mitzi, D. B., Blum, V. 2023; 7 (8)
  • Chiral Perovskite Nanoplatelets with Tunable Circularly Polarized Luminescence in the Strong Confinement Regime ADVANCED OPTICAL MATERIALS Cao, Q., Song, R., Chan, C. S., Wang, Z., Wong, P., Wong, K., Blum, V., Lu, H. 2023
  • Large Scale Quantum Chemistry with Tensor Processing Units JOURNAL OF CHEMICAL THEORY AND COMPUTATION Pederson, R., Kozlowski, J., Song, R., Beall, J., Ganahl, M., Hauru, M., Lewis, A. M., Yao, Y., Mallick, S., Blum, V., Vidal, G. 2022: 25-32


    We demonstrate the use of Googles cloud-based Tensor Processing Units (TPUs) to accelerate and scale up conventional (cubic-scaling) density functional theory (DFT) calculations. Utilizing 512 TPU cores, we accomplish the largest such DFT computation to date, with 247848 orbitals, corresponding to a cluster of 10327 water molecules with 103270 electrons, all treated explicitly. Our work thus paves the way toward accessible and systematic use of conventional DFT, free of any system-specific constraints, at unprecedented scales.

    View details for DOI 10.1021/acs.jctc.2c00876

    View details for Web of Science ID 000896935300001

    View details for PubMedID 36508260

  • The Structural Origin of Chiroptical Properties in Perovskite Nanocrystals with Chiral Organic Ligands ADVANCED FUNCTIONAL MATERIALS Kim, Y., Song, R., Hao, J., Zhai, Y., Yan, L., Moot, T., Palmstrom, A. F., Brunecky, R., You, W., Berry, J. J., Blackburn, J. L., Beard, M. C., Blum, V., Luther, J. M. 2022; 32 (25)
  • Structural descriptor for enhanced spin-splitting in 2D hybrid perovskites NATURE COMMUNICATIONS Jana, M. K., Song, R., Xie, Y., Zhao, R., Sercel, P. C., Blum, V., Mitzi, D. B. 2021; 12 (1): 4982


    Two-dimensional (2D) hybrid metal halide perovskites have emerged as outstanding optoelectronic materials and are potential hosts of Rashba/Dresselhaus spin-splitting for spin-selective transport and spin-orbitronics. However, a quantitative microscopic understanding of what controls the spin-splitting magnitude is generally lacking. Through crystallographic and first-principles studies on a broad array of chiral and achiral 2D perovskites, we demonstrate that a specific bond angle disparity connected with asymmetric tilting distortions of the metal halide octahedra breaks local inversion symmetry and strongly correlates with computed spin-splitting. This distortion metric can serve as a crystallographic descriptor for rapid discovery of potential candidate materials with strong spin-splitting. Our work establishes that, rather than the global space group, local inorganic layer distortions induced via appropriate organic cations provide a key design objective to achieve strong spin-splitting in perovskites. New chiral perovskites reported here couple a sizeable spin-splitting with chiral degrees of freedom and offer a unique paradigm of potential interest for spintronics.

    View details for DOI 10.1038/s41467-021-25149-7

    View details for Web of Science ID 000686662300003

    View details for PubMedID 34404766

    View details for PubMedCentralID PMC8371112

  • Organic-to-inorganic structural chirality transfer in a 2D hybrid perovskite and impact on Rashba-Dresselhaus spin-orbit coupling NATURE COMMUNICATIONS Jana, M. K., Song, R., Liu, H., Khanal, D., Janke, S. M., Zhao, R., Liu, C., Vardeny, Z., Blum, V., Mitzi, D. B. 2020; 11 (1): 4699


    Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chirality transfer across the organic-inorganic interface in two-dimensional hybrid perovskites using appropriate chiral organic cations. The preferred molecular configuration of the chiral spacer cations, R-(+)- or S-(-)-1-(1-naphthyl)ethylammonium and their asymmetric hydrogen-bonding interactions with lead bromide-based layers cause symmetry-breaking helical distortions in the inorganic layers, otherwise absent when employing a racemic mixture of organic spacers. First-principles modeling predicts a substantial bulk Rashba-Dresselhaus spin-splitting in the inorganic-derived conduction band with opposite spin textures between R- and S-hybrids due to the broken inversion symmetry and strong spin-orbit coupling. The ability to break symmetry using chirality transfer from one structural unit to another provides a synthetic design paradigm for emergent properties, including Rashba-Dresselhaus spin-polarization for hybrid perovskite spintronics and related applications.

    View details for DOI 10.1038/s41467-020-18485-7

    View details for Web of Science ID 000607167400003

    View details for PubMedID 32943625

    View details for PubMedCentralID PMC7499302

  • Machine learning-empowered study of metastable γ-CsPbI<sub>3</sub> under pressure and strain JOURNAL OF MATERIALS CHEMISTRY A Han, M., Peng, C., Song, R., Ke, F., Nashed, Y. G., Mao, W. L., Jia, C., Lin, Y. 2024

    View details for DOI 10.1039/d4ta00174e

    View details for Web of Science ID 001199652300001

  • Extended Honeycomb Metal Chloride with Tunable Antiferromagnetic Correlations CHEMISTRY OF MATERIALS Xue, J., Song, R., Guo, Z., Sung, H. Y., Lortz, R., Williams, I. D., Lu, H. 2023; 36 (1): 551-560
  • Exploration, Prediction, and Experimental Verification of Structure and Optoelectronic Properties in I<sub>2</sub>-Eu-IV-X<sub>4</sub> (I = Li, Cu, Ag; IV = Si, Ge, Sn; X = S, Se) Chalcogenide Semiconductors CHEMISTRY OF MATERIALS Wang, T., Mcwhorter, T. M., Wessler, G., Yao, Y., Song, R., Mitzi, D. B., Blum, V. 2023; 36 (1): 340-357
  • Chiral Cation Doping for Modulating Structural Symmetry of 2D Perovskites. Journal of the American Chemical Society Xie, Y., Morgenstein, J., Bobay, B. G., Song, R., Caturello, N. A., Sercel, P. C., Blum, V., Mitzi, D. B. 2023


    Cation mixing in two-dimensional (2D) hybrid organic-inorganic perovskite (HOIP) structures represents an important degree of freedom for modifying organic templating effects and tailoring inorganic structures. However, the limited number of known cation-mixed 2D HOIP systems generally employ a 1:1 cation ratio for stabilizing the 2D perovskite structure. Here, we demonstrate a chiral-chiral mixed-cation system wherein a controlled small amount (<10%) of chiral cation S-2-MeBA (S-2-MeBA = (S)-(-)-2-methylbutylammonium) can be doped into (S-BrMBA)2PbI4 (S-BrMBA = (S)-(-)-4-bromo-alpha-methylbenzylammonium), modulating the structural symmetry from a higher symmetry (C2) to the lowest symmetry state (P1). This structural change occurs when the concentration of S-2-MeBA, measured by solution nuclear magnetic resonance, exceeds a critical level─specifically, for 1.4 ± 0.6%, the structure remains as C2, whereas 3.9 ± 1.4% substitution induces the structure change to P1 (this structure is stable to 7% substitution). Atomic occupancy analysis suggests that one specific S-BrMBA cation site is preferentially substituted by S-2-MeBA in the unit cell. Density functional theory calculations indicate that the spin splitting along different k-paths can be modulated by cation doping. A true circular dichroism band at the exciton energy of the 3.9% doping phase shows polarity inversion and a 45 meV blue shift of the Cotton-effect-type line-shape relative to (S-BrMBA)2PbI4. A trend toward suppressed melting temperature with higher doping concentration is also noted. The chiral cation doping system and the associated doping-concentration-induced structural transition provide a material design strategy for modulating and enhancing those emergent properties that are sensitive to different types of symmetry breaking.

    View details for DOI 10.1021/jacs.3c04832

    View details for PubMedID 37531203

  • Hybrid magnonics in hybrid perovskite antiferromagnets. Nature communications Comstock, A. H., Chou, C., Wang, Z., Wang, T., Song, R., Sklenar, J., Amassian, A., Zhang, W., Lu, H., Liu, L., Beard, M. C., Sun, D. 2023; 14 (1): 1834


    Hybrid magnonic systems are a newcomer for pursuing coherent information processing owing to their rich quantum engineering functionalities. One prototypical example is hybrid magnonics in antiferromagnets with an easy-plane anisotropy that resembles a quantum-mechanically mixed two-level spin system through the coupling of acoustic and optical magnons. Generally, the coupling between these orthogonal modes is forbidden due to their opposite parity. Here we show that the Dzyaloshinskii-Moriya-Interaction (DMI), a chiral antisymmetric interaction that occurs in magnetic systems with low symmetry, can lift this restriction. We report that layered hybrid perovskite antiferromagnets with an interlayer DMI can lead to a strong intrinsic magnon-magnon coupling strength up to 0.24GHz, which is four times greater than the dissipation rates of the acoustic/optical modes. Our work shows that the DMI in these hybrid antiferromagnets holds promise for leveraging magnon-magnon coupling by harnessing symmetry breaking in a highly tunable, solution-processable layered magnetic platform.

    View details for DOI 10.1038/s41467-023-37505-w

    View details for PubMedID 37005408

  • Kinetically Controlled Structural Transitions in Layered Halide-Based Perovskites: An Approach to Modulate Spin Splitting JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Xie, Y., Song, R., Singh, A., Jana, M. K., Blum, V., Mitzi, D. B. 2022; 144 (33): 15223-15235


    Two-dimensional hybrid organic-inorganic perovskite (HOIP) semiconductors with pronounced spin splitting, mediated by strong spin-orbit coupling and inversion symmetry breaking, offer the potential for spin manipulation in future spintronic applications. However, HOIPs exhibiting significant conduction/valence band splitting are still relatively rare, given the generally observed preference for (near)centrosymmetric inorganic (especially lead-iodide-based) sublattices, and few approaches are available to control this symmetry breaking within a given HOIP. Here, we demonstrate, using (S-2-MeBA)2PbI4 (S-2-MeBA = (S)-(-)-2-methylbutylammonium) as an example, that a temperature-induced structural transition (at ∼180 K) serves to change the degree of chirality transfer to and inversion symmetry breaking within the inorganic layer, thereby enabling modulation of HOIP structural and electronic properties. The cooling rate is shown to dictate whether the structural transition occurs─i.e., slow cooling induces the transition while rapid quenching inhibits it. Ultrafast calorimetry indicates a minute-scale structural relaxation time at the transition temperature, while quenching to lower temperatures allows for effectively locking in the metastable room-temperature phase, thus enabling kinetic control over switching between distinct states with different degrees of structural distortions within the inorganic layers at these temperatures. Density functional theory further highlights that the low-temperature phase of (S-2-MeBA)2PbI4 shows more significant spin splitting relative to the room-temperature phase. Our work opens a new pathway to use kinetic control of crystal-to-crystal transitions and thermal cycling to modulate spin splitting in HOIPs for future spintronic applications, and further points to using such "sluggish" phase transitions for switching and control over other physical phenomena, particularly those relying on structural distortions and lattice symmetry.

    View details for DOI 10.1021/jacs.2c05574

    View details for Web of Science ID 000841410600001

    View details for PubMedID 35951556

  • Highly Distorted Chiral Two-Dimensional Tin Iodide Perovskites for Spin Polarized Charge Transport JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Lu, H., Xiao, C., Song, R., Li, T., Maughan, A. E., Levin, A., Brunecky, R., Berry, J. J., Mitzi, D. B., Blum, V., Beard, M. C. 2020; 142 (30): 13030-13040


    Incorporating chiral organic molecules into organic/inorganic hybrid 2D metal-halide perovskites results in a novel family of chiral hybrid semiconductors with unique spin-dependent properties. The embedded chiral organic moieties induce a chiroptical response from the inorganic metal-halide sublattice. However, the structural interplay between the chiral organic molecules and the inorganic sublattice, as well as their synergic effect on the resulting electronic band structure need to be explored in a broader material scope. Here we present three new layered tin iodide perovskites templated by chiral (R/S-)methylbenzylammonium (R/S-MBA), i.e., (R-/S-MBA)2SnI4, and their racemic phase (rac-MBA)2SnI4. These MBA2SnI4 compounds exhibit the largest level of octahedral bond distortion compared to any other reported layered tin iodide perovskite. The incorporation of chiral MBA cations leads to circularly polarized absorption from the inorganic Sn-I sublattice, displaying chiroptical activity in the 300-500 nm wavelength range. The bandgap and chiroptical activity are modulated by alloying Sn with Pb, in the series of (MBA)2Pb1-xSnxI4. Finally, we show that vertical charge transport through oriented (R-/S-MBA)2SnI4 thin films is highly spin-dependent, arising from a chiral-induced spin selectivity (CISS) effect. We demonstrate a spin-polarization in the current-voltage characteristics as high as 94%. Our work shows the tremendous potential of these chiral hybrid semiconductors for controlling both spin and charge degrees of freedom.

    View details for DOI 10.1021/jacs.0c03899

    View details for Web of Science ID 000557854400017

    View details for PubMedID 32602710

  • Molecular engineering of organic-inorganic hybrid perovskites quantum wells (vol 11, pg 1151, 2019) NATURE CHEMISTRY Gao, Y., Shi, E., Deng, S., Shiring, S. B., Snaider, J. M., Liang, C., Yuan, B., Song, R., Janke, S. M., Liebman-Pelaez, A., Yoo, P., Zeller, M., Boudouris, B. W., Liao, P., Zhu, C., Blum, V., Yu, Y., Savoie, B. M., Huang, L., Dou, L. 2021; 13 (3): 290

    View details for DOI 10.1038/s41557-020-0521-5

    View details for Web of Science ID 000551777800001

    View details for PubMedID 32704148

  • Molecular engineering of organic-inorganic hybrid perovskites quantum wells NATURE CHEMISTRY Gao, Y., Shi, E., Deng, S., Shiring, S. B., Snaider, J. M., Liang, C., Yuan, B., Song, R., Janke, S. M., Liebman-Pelaez, A., Yoo, P., Zeller, M., Boudouris, B. W., Liao, P., Zhu, C., Blum, V., Yu, Y., Savoie, B. M., Huang, L., Dou, L. 2019; 11 (12): 1151-1157


    Semiconductor quantum-well structures and superlattices are key building blocks in modern optoelectronics, but it is difficult to simultaneously realize defect-free epitaxial growth while fine tuning the chemical composition, layer thickness and band structure of each layer to achieve the desired performance. Here we demonstrate the modulation of the electronic structure-and consequently the optical properties-of organic semiconducting building blocks that are incorporated between the layers of perovskites through a facile solution processing step. Self-aggregation of the conjugated organic molecules is suppressed by functionalization with sterically demanding groups and single crystalline organic-perovskite hybrid quantum wells (down to one-unit-cell thick) are obtained. The energy and charge transfers between adjacent organic and inorganic layers are shown to be fast and efficient, owing to the atomically flat interface and ultrasmall interlayer distance of the perovskite materials. The resulting two-dimensional hybrid perovskites are very stable due to protection given by the bulky hydrophobic organic groups.

    View details for DOI 10.1038/s41557-019-0354-2

    View details for Web of Science ID 000498875700018

    View details for PubMedID 31712613

    View details for PubMedCentralID 4458893

  • Unnatural Cytosine Bases Recognized as Thymines by DNA Polymerases by the Formation of the Watson-Crick Geometry ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Zeng, H., Mondal, M., Song, R., Zhang, J., Xia, B., Liu, M., Zhu, C., He, B., Gao, Y., Yi, C. 2019; 58 (1): 130-133


    The emergence of unnatural DNA bases provides opportunities to demystify the mechanisms by which DNA polymerases faithfully decode chemical information on the template. It was previously shown that two unnatural cytosine bases (termed "M-fC" and "I-fC"), which are chemical labeling adducts of the epigenetic base 5-formylcytosine, can induce C-to-T transition during DNA amplification. However, how DNA polymerases recognize such unnatural cytosine bases remains enigmatic. Herein, crystal structures of unnatural cytosine bases pairing to dA/dG in the KlenTaq polymerase-host-guest complex system and pairing to dATP in the KlenTaq polymerase active site were determined. Both M-fC and I-fC base pair with dA/dATP, but not with dG, in a Watson-Crick geometry. This study reveals that the formation of the Watson-Crick geometry, which may be enabled by the A-rule, is important for the recognition of unnatural cytosines.

    View details for DOI 10.1002/anie.201807845

    View details for Web of Science ID 000455818400012

    View details for PubMedID 30407705