Topological Insulators – From Materials Design to Reality


  • Binghai Yan,

  • Claudia Felser,

  • Shou-Cheng Zhang


Topological insulators (TIs) are a new quantum state of matter discovered in recent years. They are beyond the spontaneous symmetry-breaking description by Landau and are instead characterized by topological invariants, and described by topological field theory. Their topological nature is similar to the quantum Hall effect, a major discovery of condensed-matter physics in 1980s (Klaus von Klitzing, Nobel Prize in Physics, 1985). The manifestation of the topological effect is the existence of robust gapless surface states inside the bulk energy gap. The topological surface states exhibit Dirac-cone-like energy dispersion with strong spin-momentum locking. Potential future applications cover areas such as spintronics, thermoelectrics, quantum computing and beyond.

It is remarkable that TIs have been realized in many common materials, without the requirement of extreme conditions such as high magnetic field and low temperature. The first TI was predicted in 2006 and experimentally realized in 2007 in HgTe quantum wells. Soon afterwards, three traditionally well-known binary chalcogenides, Bi2Se3, Bi2Te3 and Sb2Te3, were predicted and observed to be TIs with a large bulk gap and a metallic surface state consisting of a single Dirac cone. The discovery of these topological materials opened up the exciting field of topological insulators. Extensive experimental and theoretical efforts are devoted to synthesizing and optimizing samples, characterizing the topological states by surface sensitive spectroscopy, transport measurements, device fabrications, and searching for new material candidates.

The field of TIs is now expanding at a rapid pace in the communities of physics, chemistry and materials science. In this Focus Issue, we intend to present a high-quality snapshot of the materials and applications aspect of this field.

We present ten Review papers from both experiment and theory aspects. Five experimental papers [1–5] overview recent status and challenges of TI nanostructures [1], magnetotransport and induced superconductivity [2], chemistry of Bi-based TI materials [3], molecular beam epitaxial growth of TI thin films [4], and angle-resolved photoemission spectroscopy (ARPES) with circular dichroism [5]. On the other hand, five theoretical papers [6–10] report the progress from different perspectives: materials design by first-principles calculations [6, 7], the relations between TIs and thermoelectric materials [8], Floquet TIs [9], and the classification of topological states [10].

We present ten Letters that cover various aspects, ranging from ARPES, transport measurement and devices, thin film growth to first-principles simulations and fundamental theory. Letters on ARPES [11–14] report the surface states of HgTe [11], Bi2Se3 [12, 13] and Bi2Te3 [11, 14], in which the surface modification, defect doping and electron–phonon coupling are discussed; a paper on transport experiments [15] demonstrates the coexistence of electron- and hole-type charge carriers in devices of Sb2Te3/Bi2Te3 heterostructures; the growth of YPtSb thin film is reported [16], which is a Heusler compound near the boundary of topological trivial–nontrivial transition. Corresponding to the ARPES experiments, a Letter of band structure calculations [17] also reveals the effect of vacancy defects on Bi2Se3 surface states; another paper [18] shows the dependence of edge state dispersion on edge geometry of graphene. Last but not the least, two papers on phenomenological models [19, 20] report the maximally localized flat-band Hamiltonians and the spectra flow for Aharonov–Bohm rings, respectively.

We hope that this Focus Issue will be helpful for your research and stimulate more activity in the exciting field of topological insulators (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Biographical Information

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Binghai Yan received his Ph.D. in physics (ab initio study of nanostructures) from Tsinghua University, China, in 2008. He then started his Humboldt postdoctoral research in the group of Prof. Thomas Frauenheim in Bremen, Germany. Later he joined Prof. Shou-Cheng Zhang’s group in Stanford, US and focused on the theoretical study of topological insulators. Since 2012, he has been working in Prof. Claudia Felser’s group as a theory group leader in Johannes Gutenberg University of Mainz and the Max Planck Institute for Chemical Physics of Solids in Dresden, Germany. His current research concentrates on the band structure and surface chemistry of topological insulator materials.

Biographical Information

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Claudia Felser received her Ph.D. in physical chemistry from the University of Cologne, Germany, in 1994. After postdoctoral fellowships at the MPI in Stuttgart and the CNRS in Nantes (France), she joined the University of Mainz. She was a visiting scientist at Princeton University (USA) in 1999 and at Stanford University in 2009/2010, and a visiting professor at the University of Caen (France). She became a full professor at the University of Mainz in 2003. In December 2011 she became a director of the Max Planck Institute for Chemical Physics of Solids. She is the chair of the DFG research group “New Materials with High Spin Polarization” and is the director of the Graduate School of Excellence “Materials Science in Mainz” of the German Science Foundation (DFG). Her recent research focuses on the rational design of new materials for spintronics and energy technologies such as solar cells, thermoelectric materials, superconductors and topological insulators.

Biographical Information

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Shou-Cheng Zhang is the J. G. Jackson and C. J. Wood professor of physics at Stanford University. He received his BS degree from the Free University of Berlin in 1983, and his Ph.D. from the State University of New York at Stony Brook in 1987. He was a postdoc fellow at the Institute for Theoretical Physics in Santa Barbara from 1987 to 1989 and a research staff member at the IBM Almaden Research Center from 1989 to 1993. He joined the faculty at Stanford in 1993. He is a condensed matter theorist known for his work on topological insulators, spintronics and high-temperature superconductivity. He is a fellow of the American Physical Society and a fellow of the American Academy of Arts and Sciences. He received the Guggenheim fellowship in 2007, the Alexander von Humboldt research prize in 2009, Johannes Gutenberg research prize in 2010, the Europhysics prize in 2010, the Oliver Buckley prize in 2012 and the Dirac Medal and Prize in 2012 for his theoretical prediction of the quantum spin Hall effect and topological insulators.