Project involvement
Project Leader for project MT.3
Theory of non-Hermitian topology

PhD student: Lumen Eek

Co-supervisor for project 2.3C
Theory of complex magnetism

PhD student: William Huddie

Project Leader for affilated project with PhD student Anouar Moustaj

Publications in QuMat

Emergent non-Hermitian models
Lumen Eek, Anouar Moustaj, Malte Röntgen, Vincent Pagneux, Vassos Achilleos, Cristiane Morais Smith
Phys. Rev. B 109, 045122 (2024)
Compact localized boundary states in a quasi-1D electronic diamond-necklace chain
S.N. Kempkes, P. Capiod, S. Ismaili, J. Mulkens, L. Eek, I. Swart, C. Morais Smith
Quantum Frontiers 2, 1 (2023)
Fractal nodal band structures
Marcus Stålhammar and Cristiane Morais Smith
Phys. Rev. Research 5, 4 043043 (2023)
Designing Topological Monomodes in non-Hermitian System
E. Slootman, W. Cherifi, L. Eek, R. Arouca, M. Bourennane, C. Morais Smith

Arxiv: 2304.05748

Topological edge and corner states in Bi fractals on InSb
R. Canyellas, Chen Liu, R. Arouca, L. Eek, Guanyong Wang, Yin Yin, Dandan Guan, Yaoyi Li, Shiyong Wang, Hao Zheng, Canhua Liu, Jinfeng Jia, C. Morais Smith

Arxiv: 2309.0986

Brief research summary over last 5 years / academic profile

Morais Smith is a theoretical physicist whose research interests range from condensed-matter to cold-atom systems. Research in her group spans a large variety of techniques, from tight-binding models to quantum field theory, renormalization group, Schwinger-Dyson, Hubbard Stratonovich, and Chern-Simons theory. She started her career working on quantum dissipative systems and high-Tc superconductors. Later, she worked on quantum Hall systems, graphene, and topological insulators.

One of her group’s recent highlights is the development of a platform for quantum simulations in electronic systems in a collaboration with Vanmaekelbergh and Swart (UU). The technique used is based on the pioneering works by Eigler and later Manoharan, who built artificial graphene by patterning CO molecules on the surface of Cu(111). Since one can only place the COs on top of the copper atoms, which have a triangular symmetry, it was not clear whether this approach could be used to build different lattices.

First, the Morais Smith/Vanmaekelbergh/Swart collaboration showed that one can also use this platform to build square and Lieb lattices [Nature Physics 2017]. Second, they demonstrated how to control the orbital (px and py) degrees of freedom. By appropriately engineering the lattice, it was possible to lift the degeneracy of the in-plane p-orbitals [PRX 2019, ACS Nano 2020]. Third, the group proved that one can not only control the geometry of the lattice, but also its dimensionality: they created three generations of a Sierpinski fractal to show theoretically and experimentally that the electronic wavefunction lives in 1.58 dimension [Nature Physics 2019]. This work was selected as a highlight in the Nature Physics-15 years celebration (2020). Fourth, the group provided the first experimental realization of a (dipolar) higher-order topological insulator with electrons [Nature Materials 2019]. They showed that the zero modes can be created and destroyed at will by introducing defects or protrusions into the lattice. Finally, four artificial Kekule lattices were built to show that in topological crystalline insulators the existence of topological states depends strongly on the termination of the sample [PRL 2020].

In the field of ultracold atoms, her work is marked by a longstanding collaboration with the experimental group of Hemmerich on quantum simulation of condensed-matter systems. Highlights include the proposal for the realization of an artificial gauge field in bichromatic optical lattices [PRL 2007, PRL 2008], and the interaction-driven p x +ip y phase of bosons in a bipartite optical lattice [NJP 2013]. The Morais Smith-Hemmerich group also revealed how phase coherence depends on structural transitions of the lattice [NatureComm 2014] and elucidated the topological character of the Varma phase [PRL 2016].

Besides the work on quantum simulations, the Morais Smith group has proposed a thermodynamic description of topological phase transitions and actively contributed to the development of a projected quantum electrodynamics (Pseudo QED) formulation to investigate topological phases driven by interactions [PRX 2015].

International visibility, activities, prizes, scholarships etc.

Morais Smith was awarded the Winter 2019 Emmy Noether Distinction of the European Physical Society, “for her outstanding contributions to the theory of condensed matter systems and ultracold atoms to unveil novel quantum states of matter” and the 2016 Dresselhaus Prize CUI Hamburg University, Senior scientist, “for her outstanding contribution to the understanding of topological phases in two-dimensional atomic and electronic systems”. Since 2018, she is an invited member of the International Advisory Council (and a Fellow since 2019) of the T. D. Lee Institute in Shanghai Jiao-Tong University, China. In 2014 and 2015, she was awarded the prestigious High-End Foreigner Expert (HEFE) Team Award from the Chinese State Administration, together with F. Wilczek and A. Hemmerich, to be a visiting Professor at the Wilczek Quantum Center, Hangzhou, China. In the period 2013-2016, she was a recipient of the Special Visiting Professor Award of the Program Science without Borders from CNPq, Brazil. Since 2014, Morais Smith is an invited member of the Alexander von Humboldt Foundation, Germany. In 2015, she received the “Spotlight Prize” of the Utrecht Science Faculty for her exceptional visibility at the Press. In 2008, she was awarded a personal NWO-Vici grant (1.35 M€) to realize the project “Low-dimensional quantum matter: secrets between 2D and 3D” and in 2001 she obtained a Professor Boursier Grant of the Swiss National Science Foundation (1.1 MCH) to develop the project “Pattern Formation in 2D Strongly Interacting Electron Systems”.

Morais Smith has been invited to give about 300 talks (several keynote lectures) in 18 countries in Europe, Asia, Africa, and America and accepts about 20 invitations/year. Examples include Oxford, Cambridge (UK); ETH-Zürich, EPFL (CH); Harvard, Princeton, Santa Barbara, Aspen (USA); Brussels Solvay Colloquium (B); ENS Paris (F); La Sapienza-Rome (I); Max-Planck Institutes (D); Leiden (Ehrenfestii colloquium), and Veldhoven (plenary talk) (NL). Recent keynote lectures include the Annual Meeting of the Brazilian Physical Society (2020) and of the Swedish Physical Society (2019). Morais Smith has organized 43 conferences and participated in several outreach activities in museums, art galleries, cinemas. Since 2014, she is the single organizer of the EMMEPH ’t Hooft Lecture (500 people every year).

Morais Smith has supervised more than 100 students (24 Bachelor, 43 Master, 23 PhD, 15 postdocs). 10 of her 38 PhDs and PDs hold full or assistant/associate professor positions. Several of them received prestigious Prizes, such as the CNRS Bronze Medal (Mark Goerbig) or the 1000 Talents (Lih-King Lim). She is the Director of the UU Master Program in Theoretical Physics (150 students) and serves at the NWO Physics Table. She is a very active member of the Beta Faculty Diversity Committee and the organizer of the series EMMEPH, PHEMME and PHAME in 2015 & 2016.

5 key output/publications

Topological states in multi-orbital HgTe honeycomb lattices.

W. Beugeling, E. Kalesaki, C. Delerue, Y.-M. Niquet, D. Vanmaekelbergh, and C. Morais Smith, Nature Communications 6, 6316 (2015).

In this work, we theoretically predicted how to realize the spin Hall effect at room temperature by creating an artificial material, which consists of HgTe in a honeycomb geometry.

Interaction induced quantum valley Hall effect in graphene.

E.C. Marino, L.O. Nascimento, V.S. Alves, and C. Morais Smith, Physical Review X 5, 011040 (2015).

In this work, we studied theoretically the effect of the full electromagnetic interaction in 2D Dirac systems using the pseudo-QED projected formalism. We found that a universal and exact quantization of the valley Hall conductivity leads to a quantum valley Hall effect in graphene.

Proposed Spontaneous Generation of Magnetic Fields by Curved Layers of a Chiral Superconductor.
T. Kvorning, T.H. Hansson, A. Quelle, and C. Morais Smith, Physical Review Letters 120, 217002 (2018),
Editor Choice.

Featured in Volkskrant and NRC.

In this work, we theoretically predict how to identify whether a material is a chiral superconductor by measuring tiny magnetic fields that spontaneously arise upon curving the material.

Design and characterization of electrons in a fractal geometry.

S.N. Kempkes, M.R. Slot, S.E. Freeney, S.J.M. Zevenhuizen, D. Vanmaekelbergh, I. Swart, and C. Morais Smith, Nature Physics 15, 127 (2019).

Featured in Nat. Phys. News & Views, Physics Today, Science News, Pour la Science, Bild der Wissenschaft, youtube: Seeker (799K views), Multiverse (2.6K views), Volkskrant.  Selected as one of the highlights in Nat. Phys. 15years (2020).

This work is the first experimental realization of a quantum fractal. We built (theoretically and experimentally) a Sierpinski gasket and showed that the electronic wavefunction acquires the fractal dimension of the lattice.

Robust zero-energy modes in an electronic higher-order topological insulator.
S.N. Kempkes, M.R. Slot, J.J. van den Broeke, P. Capiod, W.A. Benalcazar, D. Vanmaekelbergh, D. Bercioux, I. Swart and C. Morais Smith, Nature Materials 18, 1292 (2019).

Featured in Nat. Mat. News &Views.

In this work, we realized zero-energy corner modes in a two-dimensional Kagome lattice and showed how to create or destroy them by introducing disorder at the edges.

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