#
Effects of Disorder on the Pressure-Induced Mott Transition in κ-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Cl

^{1}

^{2}

^{3}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

## 3. Results

#### 3.1. Effects of Irradiation on the Lattice Effects at the Mott Transition in $\kappa $-Cl

#### 3.2. T-p Phase Diagram for Weak Disorder

#### 3.3. Critical Behavior for Weak Disorder

#### 3.4. T-p Phase Diagrams of the Metal-Insulator Transition for Higher Irradiation Doses Based on Resistance Measurements

#### 3.5. Influence of Disorder on the Metallic and Insulating States Nearby the Mott Transition

## 4. Discussion

## 5. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

- Toyota, N.; Lang, M.; Müller, J. Low-Dimensional Molecular Metals; Springer: Heidelberg, Germany, 2007. [Google Scholar]
- Lebed, A. The Physics of Organic Superconductors and Conductors; Springer: Heidelberg, Germany, 2008. [Google Scholar]
- Mott, N.F. Metal-Insulator Transition; Wiley-VCH Verlag: Weinheim, Germany, 1990; Volume 26, p. 788. [Google Scholar]
- Imada, M.; Fujimori, A.; Tokura, Y. Metal-insulator transitions. Rev. Mod. Phys.
**1998**, 70, 1039–1263. [Google Scholar] [CrossRef] - Lee, P.A.; Nagaosa, N.; Wen, X.G. Doping a Mott insulator: Physics of high-temperature superconductivity. Rev. Mod. Phys.
**2006**, 78, 17–85. [Google Scholar] [CrossRef] - Kanoda, K.; Kato, R. Mott Physics in Organic Conductors with Triangular Lattices. Ann. Rev. Condens. Matter Phys.
**2011**, 2, 167–188. [Google Scholar] [CrossRef] - Kanoda, K. Recent progress in NMR studies on organic conductors. Hyperfine Interact.
**1997**, 104, 235–249. [Google Scholar] [CrossRef] - Miyagawa, K.; Kanoda, K.; Kawamoto, A. NMR Studies on Two-Dimensional Molecular Conductors and Superconductors: Mott Transition in κ-(BEDT-TTF)
_{2}X. Chem. Rev.**2004**, 104, 5635–5654. [Google Scholar] [CrossRef] [PubMed] - Williams, J.M.; Kini, A.M.; Wang, H.H.; Carlson, K.D.; Geiser, U.; Montgomery, L.K.; Pyrka, G.J.; Watkins, D.M.; Kommers, J.M. From semiconductor-semiconductor transition (42 K) to the highest-T
_{c}organic superconductor, κ-(ET)_{2}Cu[N(CN)_{2}]Cl (T_{c}= 12.5 K). Inorg. Chem.**1990**, 29, 3272–3274. [Google Scholar] [CrossRef] - Ito, H.; Ishiguro, T.; Kubota, M.; Saito, G. Metal-Nonmetal Transition and Superconductivity Localization in the Two-Dimensional Conductor κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl under Pressure. J. Phys. Soc. Jpn.**1996**, 65, 2987–2993. [Google Scholar] [CrossRef] - Lefebvre, S.; Wzietek, P.; Brown, S.; Bourbonnais, C.; Jérome, D.; Mézière, C.; Fourmigué, M.; Batail, P. Mott Transition, Antiferromagnetism, and Unconventional Superconductivity in Layered Organic Superconductors. Phys. Rev. Lett.
**2000**, 85, 5420–5423. [Google Scholar] [CrossRef] [PubMed] - Fournier, D.; Poirier, M.; Castonguay, M.; Truong, K.D. Mott Transition, Compressibility Divergence, and the P-T Phase Diagram of Layered Organic Superconductors: An Ultrasonic Investigation. Phys. Rev. Lett.
**2003**, 90. [Google Scholar] [CrossRef] [PubMed] - Limelette, P.; Wzietek, P.; Florens, S.; Georges, A.; Costi, T.A.; Pasquier, C.; Jérome, D.; Mézière, C.; Batail, P. Mott Transition and Transport Crossovers in the Organic Compound κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl. Phys. Rev. Lett.**2003**, 91. [Google Scholar] [CrossRef] [PubMed] - Kagawa, F.; Itou, T.; Miyagawa, K.; Kanoda, K. Transport criticality of the first-order Mott transition in the quasi-two-dimensional organic conductor κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl. Phys. Rev. B**2004**, 69. [Google Scholar] [CrossRef] - McWhan, D.B.; Menth, A.; Remeika, J.P.; Brinkman, W.F.; Rice, T.M. Metal-Insulator Transitions in Pure and Doped V
_{2}O_{3}. Phys. Rev. B**1973**, 7, 1920–1931. [Google Scholar] [CrossRef] - Limelette, P.; Georges, A.; Jérome, D.; Wzietek, P.; Metcalf, P.; Honig, J.M. Universality and Critical Behavior at the Mott Transition. Science
**2003**, 302, 89–92. [Google Scholar] [CrossRef] [PubMed] - Georges, A.; Kotliar, G.; Krauth, W.; Rozenberg, M.J. Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions. Rev. Mod. Phys.
**1996**, 68, 13. [Google Scholar] [CrossRef] - Kagawa, F.; Miyagawa, K.; Kanoda, K. Unconventional critical behaviour in a quasi-two-dimensional organic conductor. Nature
**2005**, 436, 534–537. [Google Scholar] [CrossRef] [PubMed] - Imada, M. Universality classes of metal-insulator transitions in strongly correlated electron systems and mechanism of high-temperature superconductivity. Phys. Rev. B
**2005**, 72. [Google Scholar] [CrossRef] - De Souza, M.; Brühl, A.; Strack, C.; Wolf, B.; Schweitzer, D.; Lang, M. Anomalous Lattice Response at the Mott Transition in a Quasi-2D Organic Conductor. Phys. Rev. Lett.
**2007**, 99. [Google Scholar] [CrossRef] [PubMed] - Papanikolaou, S.; Fernandes, R.M.; Fradkin, E.; Phillips, P.W.; Schmalian, J.; Sknepnek, R. Universality of Liquid-Gas Mott Transitions at Finite Temperatures. Phys. Rev. Lett.
**2008**, 100. [Google Scholar] [CrossRef] [PubMed] - Kagawa, F.; Miyagawa, K.; Kanoda, K. Magnetic Mott criticality in a κ-type organic salt probed by NMR. Nat. Phys.
**2009**, 5, 880–884. [Google Scholar] [CrossRef] - Bartosch, L.; de Souza, M.; Lang, M. Scaling Theory of the Mott Transition and Breakdown of the Grüneisen Scaling Near a Finite-Temperature Critical End Point. Phys. Rev. Lett.
**2010**, 104. [Google Scholar] [CrossRef] [PubMed] - Abdel-Jawad, M.; Kato, R.; Watanabe, I.; Tajima, N.; Ishii, Y. Universality Class of the Mott Transition. Phys. Rev. Lett.
**2015**, 114. [Google Scholar] [CrossRef] [PubMed] - Gati, E.; Garst, M.; Manna, R.S.; Tutsch, U.; Wolf, B.; Bartosch, L.; Schubert, H.; Sasaki, T.; Schlueter, J.A.; Lang, M. Breakdown of Hooke’s law of elasticity at the Mott critical endpoint in an organic conductor. Sci. Adv.
**2016**, 2. [Google Scholar] [CrossRef] [PubMed] - Zacharias, M.; Bartosch, L.; Garst, M. Mott Metal-Insulator Transition on Compressible Lattices. Phys. Rev. Lett.
**2012**, 109. [Google Scholar] [CrossRef] [PubMed] - Zacharias, M.; Rosch, A.; Garst, M. Critical elasticity at zero and finite temperature. Eur. Phys. J. Spec. Top.
**2015**, 224, 1021–1040. [Google Scholar] [CrossRef] - Terletska, H.; Vučičević, J.; Tanasković, D.; Dobrosavljević, V. Quantum Critical Transport near the Mott Transition. Phys. Rev. Lett.
**2011**, 107. [Google Scholar] [CrossRef] [PubMed] - Furukawa, T.; Miyagawa, K.; Taniguchi, H.; Kato, R.; Kanoda, K. Quantum criticality of Mott transition in organic materials. Nat. Phys.
**2015**, 11, 221–224. [Google Scholar] [CrossRef] - Lenz, B.; Manmana, S.R.; Pruschke, T.; Assaad, F.F.; Raczkowski, M. Mott Quantum Criticality in the Anisotropic 2D Hubbard Model. Phys. Rev. Lett.
**2016**, 116. [Google Scholar] [CrossRef] [PubMed] - Lee, P.A.; Ramakrishnan, T.V. Disordered electronic systems. Rev. Mod. Phys.
**1985**, 57, 287–337. [Google Scholar] [CrossRef] - Electron-Electron Interactions in Disordered Systems; Efros, A.; Pollak, M. (Eds.) North-Holland: Amsterdam, The Netherlands, 1985; Volume 10. [Google Scholar]
- Belitz, D.; Kirkpatrick, T.R. The Anderson-Mott transition. Rev. Mod. Phys.
**1994**, 66, 261–380. [Google Scholar] [CrossRef] - Anderson, P.W. Absence of Diffusion in Certain Random Lattices. Phys. Rev.
**1958**, 109, 1492–1505. [Google Scholar] [CrossRef] - Kramer, B.; MacKinnon, A. Localization: Theory and experiment. Rep. Prog. Phys.
**1993**, 56, 1469–1564. [Google Scholar] [CrossRef] - Dobrosavljević, V.; Kotliar, G. Mean Field Theory of the Mott-Anderson Transition. Phys. Rev. Lett.
**1997**, 78, 3943–3946. [Google Scholar] [CrossRef] - Byczuk, K.; Hofstetter, W.; Vollhardt, D. Mott-Hubbard Transition versus Anderson Localization in Correlated Electron Systems with Disorder. Phys. Rev. Lett.
**2005**, 94. [Google Scholar] [CrossRef] [PubMed] - Shinaoka, H.; Imada, M. Single-Particle Excitations under Coexisting Electron Correlation and Disorder: A Numerical Study of the Anderson-Hubbard Model. J. Phys. Soc. Jpn.
**2009**, 78. [Google Scholar] [CrossRef] - Byczuk, K.; Hofstetter, W.; Vollhardt, D. Competition between Anderson Localization and Antiferromagnetism in Correlated Lattice Fermion Systems with Disorder. Phys. Rev. Lett.
**2009**, 102. [Google Scholar] [CrossRef] [PubMed] - Radonjić, M.M.; Tanasković, D.; Dobrosavljević, V.; Haule, K. Influence of disorder on incoherent transport near the Mott transition. Phys. Rev. B
**2010**, 81. [Google Scholar] [CrossRef] - Bragança, H.; Aguiar, M.C.O.; Vučičević, J.; Tanasković, D.; Dobrosavljević, V. Anderson localization effects near the Mott metal-insulator transition. Phys. Rev. B
**2015**, 92. [Google Scholar] [CrossRef] - Su, X.; Zuo, F.; Schlueter, J.A.; Kini, A.M.; Williams, J.M. 80 K anomaly and its effect on the superconducting and magnetic transition in deuterated κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Br. Phys. Rev. B**1998**, 58, R2944–R2947. [Google Scholar] [CrossRef] - Yoneyama, N.; Higashihara, A.; Sasaki, T.; Nojima, T.; Kobayashi, N. Impurity Effect on the In-plane Penetration Depth of the Organic Superconductors κ-(BEDT-TTF)
_{2}X (X = Cu(NCS)_{2}and Cu[N(CN)_{2}]Br). J. Phys. Soc. Jpn.**2004**, 73, 1290–1296. [Google Scholar] [CrossRef] - Hartmann, B.; Müller, J.; Sasaki, T. Mott metal-insulator transition induced by utilizing a glasslike structural ordering in low-dimensional molecular conductors. Phys. Rev. B
**2014**, 90. [Google Scholar] [CrossRef] - Müller, J.; Hartmann, B.; Rommel, R.; Brandenburg, J.; Winter, S.M.; Schlueter, J.A. Origin of the glass-like dynamics in molecular metals κ-(BEDT-TTF)
_{2}X: Implications from fluctuation spectroscopy and ab initio calculations. New J. Phys.**2015**, 17. [Google Scholar] [CrossRef] - Yoneyama, N.; Sasaki, T.; Kobayashi, N. Substitution Effect by Deuterated Donors on Superconductivity in κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Br. J. Phys. Soc. Jpn.**2004**, 73, 1434–1437. [Google Scholar] [CrossRef] - Yoneyama, N.; Sasaki, T.; Oizumi, H.; Kobayashi, N. Impurity Effect on Superconducting Properties in Molecular Substituted Organic Superconductor κ-(ET)
_{2}Cu(NCS)_{2}. J. Phys. Soc. Jpn.**2007**, 76. [Google Scholar] [CrossRef] - Sasaki, T. Mott-Anderson Transition in Molecular Conductors: Influence of Randomness on Strongly Correlated Electrons in the κ-(BEDT-TTF)
_{2}X System. Crystals**2012**, 2, 374–392. [Google Scholar] [CrossRef] - Sasaki, T.; Oizumi, H.; Honda, Y.; Yoneyama, N.; Kobayashi, N. Suppression of Superconductivity by Nonmagnetic Disorder in Organic Superconductor κ-(BEDT-TTF)
_{2}Cu(NCS)_{2}. J. Phys. Soc. Jpn.**2011**, 80. [Google Scholar] [CrossRef] - Sano, K.; Sasaki, T.; Yoneyama, N.; Kobayashi, N. Electron Localization near the Mott Transition in the Organic Superconductor κ-(BEDT-TTF)
_{2}Cu[**N**(CN)_{2}]Br. Phys. Rev. Lett.**2010**, 104. [Google Scholar] [CrossRef] [PubMed] - Analytis, J.G.; Ardavan, A.; Blundell, S.J.; Owen, R.L.; Garman, E.F.; Jeynes, C.; Powell, B.J. Effect of Irradiation-Induced Disorder on the Conductivity and Critical Temperature of the Organic Superconductor κ-(BEDT-TTF)
_{2}Cu(SCN)_{2}. Phys. Rev. Lett.**2006**, 96. [Google Scholar] [CrossRef] [PubMed] - Miyagawa, K.; Kawamoto, A.; Nakazawa, Y.; Kanoda, K. Antiferromagnetic Ordering and Spin Structure in the Organic Conductor, κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl. Phys. Rev. Lett.**1995**, 75, 1174–1177. [Google Scholar] [CrossRef] [PubMed] - Furukawa, T.; Miyagawa, K.; Itou, T.; Ito, M.; Taniguchi, H.; Saito, M.; Iguchi, S.; Sasaki, T.; Kanoda, K. Quantum Spin Liquid Emerging from Antiferromagnetic Order by Introducing Disorder. Phys. Rev. Lett.
**2015**, 115. [Google Scholar] [CrossRef] [PubMed] - Yoneyama, N.; Furukawa, K.; Nakamura, T.; Sasaki, T.; Kobayashi, N. Magnetic Properties of X-ray Irradiated Organic Mott Insulator κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl. J. Phys. Soc. Jpn.**2010**, 79. [Google Scholar] [CrossRef] - Anzai, H.; Delrieu, J.; Takasaki, S.; Nakatsuji, S.; Yamada, J. Crystal growth of organic charge-transfer complexes by electrocrystallization with controlled applied current. J. Cryst. Growth
**1995**, 154, 145–150. [Google Scholar] [CrossRef] - Manna, R.S.; Wolf, B.; de Souza, M.; Lang, M. High-resolution thermal expansion measurements under helium-gas pressure. Rev. Sci. Instrum.
**2012**, 83. [Google Scholar] [CrossRef] [PubMed] - Guterding, D.; Diehl, S.; Altmeyer, M.; Methfessel, T.; Tutsch, U.; Schubert, H.; Lang, M.; Müller, J.; Huth, M.; Jeschke, H.O.; et al. Evidence for Eight-Node Mixed-Symmetry Superconductivity in a Correlated Organic Metal. Phys. Rev. Lett.
**2016**, 116. [Google Scholar] [CrossRef] [PubMed] - Aguiar, M.C.O.; Dobrosavljević, V. Universal Quantum Criticality at the Mott-Anderson Transition. Phys. Rev. Lett.
**2013**, 110. [Google Scholar] [CrossRef] [PubMed] - Aguiar, M.C.O.; Dobrosavljević, V.; Abrahams, E.; Kotliar, G. Effects of disorder on the non-zero temperature Mott transition. Phys. Rev. B
**2005**, 71. [Google Scholar] [CrossRef] - Efros, A.L.; Shklovskii, B.I. Coulomb gap and low temperature conductivity of disordered systems. J. Phys. C Solid State Phys.
**2001**, 8, L239–L240. [Google Scholar] [CrossRef] - Diehl, S.; Methfessel, T.; Tutsch, U.; Müller, J.; Lang, M.; Huth, M.; Jourdan, M.; Elmers, H.J. Disorder-induced gap in the normal density of states of the organic superconductor κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Br. J. Phys. Condens. Matter**2015**, 27. [Google Scholar] [CrossRef] [PubMed] - Kang, L.; Akagi, K.; Hayashi, K.; Sasaki, T. First-principles investigation of local structure deformation induced by X-ray irradiation in κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Br. Phys. Rev. B**2017**, 95. [Google Scholar] [CrossRef] - Kurosaki, Y.; Shimizu, Y.; Miyagawa, K.; Kanoda, K.; Saito, G. Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor κ-(ET)
_{2}Cu_{2}(CN)_{3}. Phys. Rev. Lett.**2005**, 95. [Google Scholar] [CrossRef] [PubMed] - Pustogow, A.; Bories, M.; Löhle, A.; Rösslhuber, R.; Zhukova, E.; Gorshunov, B.; Tomić, S.; Schlueter, J.; Hübner, R.; Hiramatsu, T.; et al. Quantum Spin Liquids Unveil the Genuine Mott State. arXiv, 2017; arXiv:1710.07241. [Google Scholar]
- Yoneyama, N.; Sasaki, T.; Kobayashi, N.; Furukawa, K.; Nakamura, T. X-ray irradiation effect on magnetic properties of Dimer-Mott insulators: κ-(BEDT-TTF)
_{2}Cu[N(CN)_{2}]Cl and β′-(BEDT-TTF)_{2}ICl_{2}. In Proceedings of the 8th International Symposium on Crystalline Organic Metals, Superconductors and Ferromagnets, Yamada Conference LXIV, Hokkaido, Japan, 12–17 September 2009. [Google Scholar]

**Figure 1.**Singular part of the relative length change ${(\Delta {L}_{b}/{L}_{b})}_{sing}$ of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl (batch #AF063) in its pristine form (data taken from Ref. [25]) (

**a**) and after exposure to X-ray irradiation for 50 h (

**b**). Data were taken along the out-of-plane b axis as a function of pressure p at constant temperatures between 30 K and 40 K.

**Figure 2.**Thermal expansion coefficient along the out-of-plane b axis, ${\alpha}_{b}$, of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl (batch #AF063) after exposure to X-ray for 50 h as a function of temperature T at constant pressures 16.5 MPa $\le \phantom{\rule{0.166667em}{0ex}}p\phantom{\rule{0.166667em}{0ex}}\le \phantom{\rule{0.166667em}{0ex}}$27.5 MPa.

**Figure 3.**Experimentally determined temperature-pressure phase diagram of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl (batch #AF063) after exposure to X-ray for 50 h. Red full squares correspond to the first-order Mott transition line extracted from the inflection point of $\Delta {L}_{b}\left(p\right)/{L}_{b}$. Cyan full circles correspond to the first-order transition line extracted from temperature-dependent measurements. The latter data points were determined by the position of the maximum ${\alpha}_{max}$ of the thermal expansion coefficient ${\alpha}_{b}\left(T\right)={L}_{b}^{-1}$ d${L}_{b}$/dT for $p\phantom{\rule{0.166667em}{0ex}}<\phantom{\rule{0.166667em}{0ex}}{p}_{c}$. Red open symbols correspond to the Widom line. Open cyan symbols correspond to a crossover line, determined by the position of ${\alpha}_{max}$ for $p\phantom{\rule{0.166667em}{0ex}}>\phantom{\rule{0.166667em}{0ex}}{p}_{c}$. Red- and blue-shaded areas delimited by the broken lines in the same color code indicate the experimentally determined width of the features along the b axis and can be assigned to the disorder-related (red) and the criticality-related (blue) crossover regimes, respectively. The broken lines represent, within the error margins, the full width at half maximum of the peaks in dL/dP. The brown dashed line corresponds to the ${p}_{c}\left(T\right)$ curve extracted from a fit of the data, presented in Figure 1 to the mean-field model of Equation (1) (see text for details). The first-order transition line (dark grey line), the Widom line (light grey line) and the critical endpoint (black open circle) for a pristine crystal of batch #AF063 [25] are given for comparison.

**Figure 4.**Singular part of the relative length change of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl along the out-of-plane b axis, ${(\Delta {L}_{b}/{L}_{b})}_{sing}$, (open symbols) as a function of pressure p at various temperatures 30 K $\le T\le \phantom{\rule{0.166667em}{0ex}}$43 K, together with a fit (straight lines) based on the mean-field solution, given by Equation (1). Black open symbols and red straight lines represent results on a pristine sample of batch #AF063, which were published in Ref. [25]. Blue open symbols and orange lines represent results on a crystal of batch #AF063 which was exposed to X-ray for 50 h.

**Figure 5.**Out-of-plane resistance R of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl (crystal #5-7), which was exposed to X-ray irradiation for 50 h (

**a**); 100 h (

**b**) and 150 h (

**c**), as a function of temperature T at various constant pressure values 0 MPa$\phantom{\rule{0.166667em}{0ex}}\le \phantom{\rule{0.166667em}{0ex}}p\phantom{\rule{0.166667em}{0ex}}\le \phantom{\rule{0.166667em}{0ex}}$100 MPa upon warming and upon cooling.

**Figure 6.**T-p phase diagram of the first-order Mott metal-insulator transition line of $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl upon increasing disorder which was intentionally introduced by X-ray irradiation. Black circles correspond to the phase transition line obtained from measurements (not shown) on a pristine sample of batch #AF063. Dark blue and light blue circles correspond to the phase transition line obtained from measurements on the same sample of batch #5-7 after exposure to X-ray for 50 h and 100 h, respectively (see Figure 5). Note that pairs of data points taken at the same p value correspond to the position of the jump upon warming and cooling. The lines are guides to the eyes. In case of 150 h no discontinuities in $R(T,p)$ could be resolved signaling the absence of a strong first-order phase transition.

**Figure 7.**Experimentally determined T-p phase diagrams for a $\kappa $-(BEDT-TTF)${}_{2}$Cu[N(CN)${}_{2}$]Cl crystal of batch #5-7 after exposure to X-ray for 50 h (

**a**); 100 h (

**b**) and 150 h (

**c**). Data were extracted from the resistance R measurements presented in Figure 5. Green symbols in (

**a**,

**b**) represent the first-order transition line extracted from cooling as well as warming experiments, the black-edged big green circle marks the second-order critical endpoint. After exposure to X-ray for 150 h (

**c**) no discontinuities in $R(T,p)$ indicating a first-order phase transition could be resolved. White circles indicate the temperature, below which a sizable hysteresis between warming and cooling was observed. White hatched area is a guide to the eye for the hysteresis region, delimited by the white circles. Dark grey symbols mark the entrance into a spurious superconducting (sp-sc) state. Light grey symbols indicate the transition into a bulk superconducting (sc) state. Lines are guide to the eyes. The background shows a contour plot of $log\left(R\right(T,p)/\mathsf{\Omega})$. Dashed lines indicate three constant-resistance lines with $log(R/\mathsf{\Omega})$ = 2.5 $\mathsf{\Omega}$, $log(R/\mathsf{\Omega})$ = 3 $\mathsf{\Omega}$ and $log(R/\mathsf{\Omega})$ = 3.5 $\mathsf{\Omega}$.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Gati, E.; Tutsch, U.; Naji, A.; Garst, M.; Köhler, S.; Schubert, H.; Sasaki, T.; Lang, M.
Effects of Disorder on the Pressure-Induced Mott Transition in *κ*-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Cl. *Crystals* **2018**, *8*, 38.
https://doi.org/10.3390/cryst8010038

**AMA Style**

Gati E, Tutsch U, Naji A, Garst M, Köhler S, Schubert H, Sasaki T, Lang M.
Effects of Disorder on the Pressure-Induced Mott Transition in *κ*-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Cl. *Crystals*. 2018; 8(1):38.
https://doi.org/10.3390/cryst8010038

**Chicago/Turabian Style**

Gati, Elena, Ulrich Tutsch, Ammar Naji, Markus Garst, Sebastian Köhler, Harald Schubert, Takahiko Sasaki, and Michael Lang.
2018. "Effects of Disorder on the Pressure-Induced Mott Transition in *κ*-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Cl" *Crystals* 8, no. 1: 38.
https://doi.org/10.3390/cryst8010038